The intensity of a sound wave is given as 5.42 W/m².
If its intensity is raised by 12.4 decibels, we are to find the new intensity of the sound wave in W/m².
Formula relating intensity and decibel is; dB = 10 log (I/I₀)⇒ I/I₀ = antilog (dB/10)Where, I₀ is the threshold of hearing. Sound intensity ratio in (dB) = 12.4So, new intensity = I = I₀ antilog (dB/10) = 1 x antilog (12.4/10)W/m².
Therefore, new intensity = 1.5 x 5.42 W/m² = 8.13 W/m².Hence, the new intensity (in W/m²) is 8.13 W/m².
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Q2. a) What is the circumference of a circle of
radius a? [3 pts]
b) What symbol represents the time it takes the
planet to complete a full orbit around the Sun? [3 pts]
c) Given that velocity = dista
The circumference of a circle is equal to 2π multiplied by the radius of the circle. The circumference of a circle with a radius of a is: 2πa
The circumference of a circle is the distance around the circle. This distance is the length of the curved line around the circle, and it is always the same for any circle, no matter what size it is. The circumference of a circle can be calculated by using the formula 2πr, where r is the radius of the circle. The value of π is a mathematical constant that represents the ratio of the circumference of a circle to its diameter. This value is approximately equal to 3.14159. Therefore, the circumference of a circle with a radius of a is 2πa. The circumference of a circle is an important concept in geometry, as it is used to calculate the diameter of a circle. The perimeter of a circle is the distance around the outside edge of the circle. It is important to note that the perimeter of a circle is not the same as the area of a circle, which is the amount of space inside the circle.
The symbol that represents the time it takes a planet to complete a full orbit around the Sun is T. This symbol is often used in physics and astronomy to represent the period of an object's orbit. The period of an orbit is the time it takes for an object to complete one full revolution around another object. In the case of a planet, the period of its orbit around the Sun is determined by its distance from the Sun and the gravitational force between the two objects.
Given that velocity = distance/time, what is the equation for time?
The equation for time can be derived from the formula for velocity,
which is:
velocity = distance/time
By rearranging this formula, we can solve for time: time = distance/ velocity
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A point charge Qs = 48.OnC is placed on the positive y-axis at (x1=0.00m, y1=1.33m), and a second point charge Q2= -32.0nC is placed at the origin (x2 = 0 m, y2=0m). what is the electric field at point "P" located on the x-axis at (xp=2.70, Yp=0.00m)?
The electric field at point P located on the x-axis at (xP=2.70, yP=0.00m) is 8.6 N/C.
The electric field at point P located on the x-axis at (xP=2.70m, yP=0.00m) can be calculated as follows:
Q1= 48.0 nC = 48 x 10⁻⁹CC is located at (x1=0.00m, y1=1.33m)
Q2= -32.0 nC = -32 x 10⁻⁹C is located at (x2=0.00m, y2=0.00m)
Distance of P from Q1, r1 = √[(xP-x1)² + (yP-y1)²] = √[(2.70-0)² + (0-1.33)²] = 2.58m
Distance of P from Q2, r2 = √[(xP-x2)² + (yP-y2)²] = √[(2.70-0)² + (0-0)²] = 2.70m
The electric field at point P can be calculated using the formula of the electric field for point charge;
E1 = kQ1 / r₁² = (9.0 x 10⁹ Nm²/C²) x (48 x 10⁻⁹ C) / (2.58m)² = 19.5 N/C (along the negative y-axis)
E2 = kQ2 / r₂² = (9.0 x 10⁹ Nm²/C²) x (-32 x 10⁻⁹ C) / (2.70m)² = -10.9 N/C (along the positive x-axis)
Net electric field at point P;
E = E₁ + E₂ = 19.5 N/C - 10.9 N/C = 8.6 N/C
Therefore, the electric field at point P located on the x-axis at (xP=2.70, yP=0.00m) is 8.6 N/C.
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The capacitance of an empty capacitor is 6.60 uF. The capacitor is connected to a 12-V battery and charged up. With the capacitor connected to the battery, a slab of dielectric material is inserted between the plates. As a result, 5.00 x 105 C of additional charge flows from one plate, through the battery, and onto the other plate. What is the dielectric constant of the material?
The dielectric constant of the material can be calculated from the capacitance of the capacitor with the dielectric slab, given that the capacitance with an empty capacitor is 6.60 uF and that 5.00 x 10⁵ C of additional charge flows through the battery.
What is the dielectric constant of the material?
The formula used for the calculation of the dielectric constant of the material is given by;`C = (Kε_0A)/d`Where,K = dielectric constantε₀ = vacuum permittivity (8.85 x 10⁻¹² F/m)d = separation of platesA = area of the plateC = capacitance of the capacitorGiven that the capacitance of the empty capacitor `C = 6.60 uF`Charge flown = `Q = 5.00 x 10⁵ C`Voltage = `V = 12 V`From the formula for capacitance,`C = Q/V`
The capacitance of the capacitor with the dielectric material can be calculated by adding the additional charge flown into the capacitor to the initial charge.`C' = (Q + 5.00 x 10⁵ C)/V``C' = (Q/V) + (5.00 x 10⁵ C)/V``C' = 6.60 + 5.00 x 10⁵ / 12`The capacitance with the dielectric material `C' = 6.60 + 41667 F` `= 41673.3 F`The dielectric constant of the material can be calculated by substituting the values of the capacitance of the capacitor with the dielectric material and that of the vacuum permittivity into the formula for capacitance.`
C' = (Kε_0A)/d``K = (C'd)/(ε₀A)`Substituting the values into the above formula;`K = (41673.3 x 3.8 x 10⁻¹¹)/(3.6 x 10⁻⁴)` `= 4398.3`
Hence, the dielectric constant of the material is 4398.3.
How to calculate the dielectric constant of the material?
The dielectric constant of the material can be calculated from the capacitance of the capacitor with the dielectric slab, given that the capacitance with an empty capacitor is 6.60 uF and that 5.00 x 10⁵ C of additional charge flows through the battery.
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Which of the following magnetic fluxes is zero? OB = 4Tî - 3T and A = 3m%î + 3m - 4mºk OB = 4Tî - 3T and A = 3m2 - 3m + 4m²k B = 4T î - 3TÂ B and A= 3m2 – 3m B = 4T - 3Tk and Ā= - 3mºj + 4m
The magnetic flux is given by the dot product of the magnetic field (B) and the area vector (A). If the dot product is zero, it means the magnetic flux is zero. So the correct option is d) B = 4T - 3Tk and Ā= - 3mºj + 4m.
Looking at the given options:
a) OB = 4Tî - 3T and A = 3m%î + 3m - 4mºk
b) OB = 4Tî - 3T and A = 3m2 - 3m + 4m²k
c) B = 4T î - 3TÂ and A= 3m2 – 3m
d) B = 4T - 3Tk and Ā= - 3mºj + 4m
To determine if the magnetic flux is zero, we need to calculate the dot product B · A for each option. If the dot product equals zero, then the magnetic flux is zero.
Option a) B · A = (4Tî - 3T) · (3m%î + 3m - 4mºk) = 0 (cross product between î and k)
Option b) B · A = (4Tî - 3T) · (3m2 - 3m + 4m²k) ≠ 0 (terms with î and k are non-zero)
Option c) B · A = (4T î - 3TÂ) · (3m2 – 3m) ≠ 0 (terms with î and  are non-zero)
Option d) B · Ā = (4T - 3Tk) · (-3mºj + 4m) = 0 (cross product between k and j)
Therefore, the magnetic flux is zero for option d) B = 4T - 3Tk and Ā= - 3mºj + 4m.
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A 380 V, 50 Hz, 960 rpm, star-connected induction machine has the following per phase parameters referred to the stator: Magnetizing reactance, R. = 75 12; core-loss resistance, Xm = 500 S2; stator winding resistance, R= 2 12; stator leakage reactance, X1 = 3.2; rotor winding resistance, R2 = 3.2; rotor leakage reactance, X2 22. Friction and windage losses are negligible. Based on the approximate equivalent circuit model, a) Calculate the rated output power and torque of the machine. (5 marks) b) Calculate the starting torque, stator starting current and power factor.
A) The rated output power and torque of the machine are approximately 50 kW and 151.92 Nm, respectively.
b) The starting torque is approximately 94.73 Nm, the stator starting current is approximately 57.14 A, and the power factor is approximately 0.8 lagging.
A) Calculation of rated output power and torque:
Rated Output Power (P) = (3 * V² * R) / (Z_total * 2)
P = (3 * (380 V)² * 5.2 Ω) / ((5.2 + j100.2) Ω * 2)
P ≈ 50 kW
Rated Torque (T) = (P * 1000) / (2 * π * n_r)
T = (50 kW * 1000) / (2 * π * (960 rpm * (2π rad/1 min)))
T ≈ 151.92 Nm
b) Calculation of starting torque, stator starting current, and power factor:
Starting Torque (T_start) = (3 * V² * R₂) / (s * Z_total)
T_start = (3 * (380 V)² * 3.2 Ω) / (1 * (5.2 + j100.2) Ω)
T_start ≈ 94.73 Nm
Stator Starting Current (I_start) = (V / Z_total) * (R / √(R² + X²))
I_start = (380 V / (5.2 + j100.2) Ω) * (5.2 Ω / √(5.2² + 100.2²) Ω)
I_start ≈ 57.14 A
Power Factor (cos(θ)) = R / √(R² + X²)
cos(θ) = 5.2 Ω / √(5.2² + 100.2²) Ω
cos(θ) ≈ 0.8
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A turbofan aircraft produces a noise with sound power of 1,000 W during full throttle at take-off. If you are standing on the tarmac 400 m from the plane, what sound level would you hear? What is the minimum safe distance from the propeller that is needed to ensure you don't experience a sound above the threshold of pain?
The sound level you hear is 100 dB and the minimum safe distance from the propeller is 1 meter (approximately).
The equation that is used to calculate sound intensity is given by
I = W/A,
where
W is the sound power
A is the area of the sphere
We can calculate the intensity of sound using the equation given above. Let's calculate the sound level you would hear using the formula
L = 10log(I/I₀),
where
L is the sound level
I₀ is the threshold of hearing
Here, we have to take
I₀ = 10⁻¹² W/m²
We know that the sound power of the turbofan aircraft is 1,000 W.
So, the intensity of sound produced by the turbofan aircraft is:
I = W/A
Therefore,
I = 1,000/4π × 400²
I = 0.049 W/m²
Using the equation
L = 10log(I/I₀),
we can calculate the sound level that you would hear:
L = 10log(I/I₀)
Therefore, L = 10log(0.049/10⁻¹²) = 100 dB(A)
The minimum safe distance from the propeller that is needed to ensure you don't experience a sound above the threshold of pain is 1 meter (approximately).
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A car initially traveling eastward turns north by traveling in a circular path at a uniform speed as shown in the figure below. The length of the arc ABC is 222 m, and the car completes the turn in 34.0 s.
An x y coordinate axis is shown. Point A is located at a negative value on the y-axis, and an arrow points from the point A to the right. A dotted line curves up and to the right in a quarter circle until it reaches point C on the positive x-axis. An arrow points directly upward from point C. Point B is on the dotted circle. A line drawn from the origin to point B makes an angle of 35.0° below the x-axis.
(a) Determine the car's speed.
m/s
(b) What is the magnitude and direction of the acceleration when the car is at point B?
magnitude m/s2
direction ° counterclockwise from the +x-axis
A car initially traveling eastward turns north in a circular path, covering an arc length of 222 m in 34.0 s. A line drawn from the origin to point B makes an angle of 35.0° below the x-axis. The speed of the car is 6.53 m/s and acceleration at B is [tex]0.336 m/s^2[/tex].
(a) To determine the car's speed, we can use the formula v = s/t, where v represents the velocity (speed), s represents the distance traveled, and t represents the time taken. In this case, the distance traveled is the length of the arc ABC, which is given as 222 m, and the time taken is given as 34.0 s. Substituting these values into the formula, we have:
v = [tex]\frac{ 222 }{34}[/tex] = [tex]6.53 m/s[/tex]
Therefore, the car's speed is [tex]6.53 m/s.[/tex]
(b) To find the magnitude of the acceleration at point B, we can use the formula a = [tex]v^2 / r[/tex], where a represents acceleration, v represents velocity, and r represents the radius of the circular path. From the given figure, we can see that the radius of the circular path is the distance from the origin to point B.
Using trigonometry, we can find the radius as follows:
r = BC = AB * [tex]sin(35°) = 222 m * sin(35°)[/tex] ≈ [tex]126.83 m[/tex]
Substituting the values into the formula, we have:
a = [tex](6.53 m/s)^2[/tex] / [tex]126.83 m[/tex] ≈ [tex]0.336 m/s^2[/tex]
Therefore, the magnitude of the acceleration at point B is approximately [tex]0.336 m/s^2[/tex].
(c) To determine the direction of the acceleration, we need to consider the circular motion. At point B, the acceleration is directed towards the center of the circle. Since the car is turning from east to north, the direction of the acceleration would be counterclockwise. The angle between the acceleration and the +x-axis can be determined as follows:
Angle = [tex]90° - 35° = 55°[/tex]
Therefore, the direction of the acceleration at point B is approximately 55° counterclockwise from the +x-axis.
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Name the type of force applied by a flat road to a tire when a car is turning right without skidding (maybe in a circle) and then name the type of force applied when the car is skidding on, say, a wet road.
a. only the normal force in both situations b. static friction in both situations c. kinetic friction in both situations d. static friction, kinetic friction e. kinetic friction, static friction
Select each case where it would be appropriate to use joules as the ONLY unit for your answer:
When you are finding: [there is more than one answer]
a. energy
b. power
c. potential energy
d. kinetic energy
e. heat energy
f. force constant of a spring
When you are finding energy, potential energy, kinetic energy, and heat energy, it would be appropriate to use joules as the ONLY unit for your answer, and the answer is (a, c, d, e).
The type of force applied by a flat road to a tire when a car is turning right without skidding and then the type of force applied when the car is skidding on, say, a wet road are as follows:a. only the normal force in both situations. In the absence of skidding, the tire will roll on the road, producing a force that opposes the direction of motion but does not change the magnitude of the tire's velocity. This force is known as the force of static friction.Static friction in both situations is d. static friction, kinetic friction. When you are finding energy, potential energy, kinetic energy, and heat energy, it would be appropriate to use joules as the ONLY unit for your answer, and the answer is (a, c, d, e).
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A grandfather clock is controlled by a swinging brass pendulum that is 1.6 m long at a temperature of 28°C. (a) What is the length of the pendulum rod when the temperature drops to 0.0°C? (Give your answer to at least four significant figures.) mm (b) If a pendulum's period is given by T = 2√ L/g, where L is its length, does the change in length of the rod cause the clock to run fast or slow? O fast O slow Oneither The density of lead is 1.13 x 104 kg/m³ at 20.0°C. Find its density (in kg/m³) at 125°C. (Use a = 29 x 106 (°C) for the coefficient of linear expansion. Give your answer to at least four significant figures.) 4
(a) The length of the pendulum rod when the temperature drops to 0.0°C is: L' = L + ΔL= 1.6 m - 8.96 × 10⁻⁴ m= 1.5991 m≈ 1.599 m .(b)Therefore, the change in length of the rod causes the clock to run fast.
a. In order to find the length of the pendulum rod when the temperature drops to 0.0°C,
formula;`ΔL = L α ΔT`ΔL = change in length , L = initial lengthα = coefficient of linear expansionΔT = change in temperature
We can find the change in length as follows:ΔL = L α ΔT= 1.6 m × 18 × 10⁻⁶/°C × (-28)°C= -8.96 × 10⁻⁴ m
The minus sign indicates that the length has decreased.
Thus the length of the pendulum rod when the temperature drops to 0.0°C is: L' = L + ΔL= 1.6 m - 8.96 × 10⁻⁴ m= 1.5991 m≈ 1.599 m or 1599 mm (to four significant figures)
b. We know that the period of a pendulum is given by;T = 2π√ L/gWhere, L = Length of the pendulum g = Acceleration due to gravity π = 3.14T is directly proportional to the square root of L.
Hence, a decrease in length of the pendulum will cause the clock to run fast.
This is because, as the length decreases, the time period will also decrease which means the clock will tick faster.
Therefore, the change in length of the rod causes the clock to run fast.
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A major leaguer hits a baseball so that it leaves the bat at a speed of 31.0 m/sm/s and at an angle of 35.3 ∘∘ above the horizontal. You can ignore air resistance.
C. Calculate the vertical component of the baseball's velocity at each of the two times you found in part A.
Enter your answer as two numbers, separated by a comma, in the order v1v1, v2v2.
D.What is the magnitude of the baseball's velocity when it returns to the level at which it left the bat?
E.What is the direction of the baseball's velocity when it returns to the level at which it left the bat?
A.baseball at a height of 8.50 m is 0.560,3.10
B. horizontal component is 25.3,25.3
A) the vertical component of velocity -5.488 m/s. B) The vertical component of velocity at the second time is approximately -30.38 m/s. C) The magnitude of the baseball's velocity is approximately 25.3 m/s. D) 35.3 degrees above the horizontal. E) Upward at an angle of 35.3 degrees above the horizontal.
The vertical component of the baseball's velocity at the two times can be calculated using the initial vertical velocity and the time of flight. From part A, we found that the time of flight is approximately 0.560 seconds and 3.10 seconds.
To calculate the vertical component of velocity at the first time (0.560 seconds), we can use the formula v1y = v0y + gt, where v1y is the vertical component of velocity at time 0.560 seconds, v0y is the initial vertical component of velocity, g is the acceleration due to gravity (approximately -9.8 m/s^2), and t is the time. Plugging in the values, we have:
v1y = 0 + (-9.8)(0.560) = -5.488 m/s
Therefore, the vertical component of velocity at the first time is approximately -5.488 m/s.
Similarly, to calculate the vertical component of velocity at the second time (3.10 seconds), we use the same formula:
v2y = v0y + gt
v2y = 0 + (-9.8)(3.10) = -30.38 m/s
Therefore, the vertical component of velocity at the second time is approximately -30.38 m/s.
Moving on to part D, to find the magnitude of the baseball's velocity when it returns to the level at which it left the bat, we need to consider that the vertical component of velocity at that point is zero. This is because the baseball reaches its maximum height and starts descending, crossing the level at which it left the bat. Since the vertical component is zero, we only need to consider the horizontal component of velocity at that point. From part B, we found that the horizontal component of velocity is approximately 25.3 m/s. Therefore, the magnitude of the baseball's velocity when it returns to the level at which it left the bat is approximately 25.3 m/s.
Finally, in part E, the direction of the baseball's velocity when it returns to the level at which it left the bat can be determined from the angle of 35.3 degrees given in the problem. Since the vertical component of velocity is zero at this point, the direction of the velocity is solely determined by the horizontal component. The angle of 35.3 degrees above the horizontal indicates that the baseball is returning in an upward direction. Thus, the direction of the baseball's velocity when it returns to the level at which it left the bat is upward at an angle of 35.3 degrees above the horizontal.
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Air, a mixture of nitrogen and oxygen, has an effective molar mass of 0.029 kg/mol.
What is the speed of sound in the stratosphere, 20 km above the earth’s surface, where the temperature is –80∘C ?
Express your answer with the appropriate units.
The speed of sound in the stratosphere is 337.5 m/s.
The given molar mass of the air is 0.029 kg/mol.Using the ideal gas equation, the speed of sound can be calculated using the following equation: v = √(γR × T/M)where v is the speed of sound, γ is the specific heat ratio, R is the universal gas constant, T is the temperature, and M is the molar mass.The value of the specific heat ratio for air is γ = 1.4The value of the universal gas constant is R = 8.31 J/mol·K.
The value of the temperature of the stratosphere, T = -80°C = 193 K. The value of the molar mass of air is M = 0.029 kg/mol.Substituting these values into the equation, we get:v = √(1.4 × 8.31 × 193 / 0.029) = 337.5 m/sTherefore, the speed of sound in the stratosphere is 337.5 m/s .
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Sound is detected when a sound wave causes the eardrum to vibrate. If the diameter of your eardrum is 7.5 mm, what is the sound intensity level that delivers 4.4 p) of energy to your eardrum each second? 30 dB 35 dB 40 dB 45 dB 50 dB 55 dB 60 dB 65 dB
The sound intensity level that delivers 4.4 p) of energy to the eardrum each second with a 7.5 mm diameter is 40 dB.
Sound intensity level is measured in decibels (dB) and is a logarithmic scale used to quantify the loudness of a sound. The formula to calculate sound intensity level in decibels is given by:
[tex]L = 10 * log10(I/I_0)[/tex]
Where L is the sound intensity level, I is the sound intensity, and I₀ is the reference intensity (usually taken as the threshold of hearing, which is [tex]10^{(-12)}[/tex]watts per square meter).
To solve this problem, we need to find the sound intensity level when 4.4 p) (which stands for [tex]4.4 * 10^{(-12)}[/tex]) of energy is delivered to the eardrum each second. We can substitute the values into the formula:
[tex]40 = 10 * log10(4.4 * 10^{(-12)}/I_0)[/tex]
Simplifying the equation, we get:
[tex]log10(4.4 * 10^{(-12)}/I_0) = 4[/tex]
Taking the antilogarithm of both sides, we find:
[tex]4.4 * 10^{(-12)}/I_0= 10^4[/tex]
Solving for [tex]I_o[/tex], we get:
[tex]I_0= 4.4 * 10^{(-12)}/10^4 = 4.4 * 10^{(-16)}[/tex]
Therefore, the sound intensity level that delivers 4.4 p) of energy to the eardrum each second is 40 dB.
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Two crates, of mass m1m1 = 64 kgkg and m2m2 = 123 kgkg , are in contact and at rest on a horizontal surface. A 700 NNforce is exerted on the 64 kgkg crate.
I need help with question c and d
c) Repeat part A with the crates reversed.
d) Repeat part B with the crates reversed.
part a and b ---> If the coefficient of kinetic friction is 0.20, calculate the acceleration of the system. = 1.8 m/s^2
Calculate the force that each crate exerts on the other. = 460 N
part(c) Hence, the acceleration of the system is 3.74 m/s². part(d) Hence, the force that each crate exerts on the other is 119.2 N.
Part (c): If we reverse the crates, that is, if 123 kg mass crate comes in contact with 64 kg mass crate and a force of 700 N is applied on 123 kg crate,
Then the acceleration can be calculated as follows: We need to find the acceleration of the system, which can be calculated using the formula, Total force, F = ma
Where, F = 700 N (force applied on the system)m = m1 + m2 = 64 kg + 123 kg = 187 kg a = acceleration of the system
Hence, the acceleration of the system is 3.74 m/s²
Part (d): If we reverse the crates, then the force that each crate exerts on the other can be calculated as follows:
Let us assume that f is the force that each crate exerts on the other. Then, f is given by:
From the free-body diagram of the 64 kg crate, we have:fn1 = Normal force exerted by the surface on the 64 kg cratefr1 = force of friction acting on the 64 kg crate due to contact with the surface
From the free-body diagram of the 123 kg crate, we have:fn2 = Normal force exerted by the surface on the 123 kg cratefr2 = force of friction acting on the 123 kg crate due to contact with the surface.
Then we have the equations: For the 64 kg crate,fn1 - f = m1 * a ... (1)where a is the acceleration of the system.
As we have calculated a in part (a), we can substitute the value of a into the equation and solve for f.
For the 123 kg crate,fn2 + f = m2 * a ... (2)From equation (2), we have, f = (m2 * a - fn2)
From equation (1), we have,fn1 - f = m1 * afn1 - f = m1 * 1.8fn1 - f = 64 * 1.8fn1 - f = 115.2fn1 = 115.2 + ff = fn1/2 + fn1/2 - m2 * a + fn2/2f = 230.4/2 - (123 * 3.74) + 580.8/2
Hence, the force that each crate exerts on the other is 119.2 N.
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Boltzmann approximations to the Fermi-Dirac distribution functions are only valid when: (a) The Fermi level is mid-gap; (b) The electron and hole effective masses are equal; (c) The temperature is very low; (d) The Fermi level is thermally far removed from the band edges; (e) All of the above; (f) None of the above;
Boltzmann approximations to the Fermi-Dirac distribution functions are only valid when the Fermi level is thermally far removed from the band edges, therefore the answer is option (d).
Fermi-Dirac Distribution Function
The Fermi-Dirac distribution function is a probability function used in quantum statistics to describe the likelihood of discovering electrons in different energy levels in a system at thermal equilibrium.
It was created by Enrico Fermi and Paul Dirac as a modification of the classical Maxwell–Boltzmann distribution function for particles with half-integer spin. Boltzmann approximations are only valid when the Fermi level is thermally far removed from the band edges.
It is impossible to calculate the exact Fermi function in general. This is due to the fact that the energy integrals in the expression cannot be performed explicitly. Boltzmann approximations can be used to solve this problem.
When the temperature is high and the Fermi energy is far away from the conduction and valence band edges, the Boltzmann approximation is very accurate. At low temperatures, the Fermi-Dirac function reduces to a step function.
Thus, Boltzmann approximations to the Fermi-Dirac distribution functions are only valid when the Fermi level is thermally far removed from the band edges, therefore the answer is option (d).
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Find the wavelength of a 108 Hz EM wave.
The wavelength of the given EM wave is 2.78 × 10^6 m
The given EM wave has a frequency of 108 Hz. The wavelength (λ) of a wave can be calculated using the equation
λ = c / f, where c is the speed of light and f is the frequency of the wave.
Therefore, the wavelength of a 108 Hz EM wave can be calculated as follows:
λ = c / f = (3.00 × 10^8 m/s) / (108 Hz) = 2.78 × 10^6 m, or approximately 2.78 million meters.
Therefore, the wavelength of the given EM wave is 2.78 × 10^6 m
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(a) A block of mass 2.00 kg is pushed 2.20 m along a frictionless horizontal table by a constant 16.7N force directed 27.5° below th horizontal. Determine the work done by the applied force (in Joules).b) Determine the magnitude of the normal force exerted by the table. (c) Determine the magnitude of the force of gravity. (d) Determine the magnitude of the net force on the block.
The magnitude of the normal force exerted by the table is 17.5 N.(c) The magnitude of the force of gravity is the weight of the block, which is 19.6 N. Therefore, the magnitude of the force of gravity is 19.6 N.(d) To find the magnitude of the net force on the block, we need to resolve the applied force into horizontal and vertical components. We can find the vertical component using the formula:
Vertical component of applied force = F sin θ Where,F = 16.7 N is the force applied θ = 27.5° below the horizontal is the angle between the force and the displacement F sin θ = 16.7 sin 27.5°= 7.67 NThe net force is the vector sum of the horizontal and vertical components of the applied force and the force of gravity.Net force = Force in the horizontal direction − Force in the vertical direction= F cos θ − mg= 16.7 cos 27.5° − 2.00 kg × 9.8 m/s²= 14.2 N Therefore, the magnitude of the net force on the block is 14.2 N.
(a) The work done by the applied force (in Joules) is 51.4J. Work done = Force x distance moved along the force = F cos θ x d = (16.7cos27.5°) x 2.2 = 51.4J(b) The magnitude of the normal force exerted by the table is 19.1N. Normal force = mg cosθ = 2 x 9.8cos27.5° = 19.1N(c) The magnitude of the force of gravity is 19.6N. Force of gravity = mg = 2 x 9.8 = 19.6N(d) The magnitude of the net force on the block is 14.2N. The vertical component of the applied force is F sin θ = 16.7sin27.5° = 7.7N. Net force = F cosθ - mg = 16.7cos27.5° - 2 x 9.8 = 14.2N. Therefore, the magnitude of the net force on the block is 14.2N.
A block of mass 2.00 kg is pushed 2.20 m along a frictionless horizontal table by a constant 16.7 N force directed 27.5 ° below the horizontal. The solution is explained step by step below:(a) To determine the work done by the applied force (in Joules), we have to use the formula: Work done = Force x distance moved along the forceW = F × dW = F cos θ × dWhere,F = 16.7 N is the force appliedθ = 27.5° below the horizontal is the angle between the force and the displacementd = 2.20 m is the distance moved along the forceNow, F cos θ = 16.7 cos 27.5°= 14.9 NW = F cos θ × d= 14.9 N × 2.20 m= 32.8 J
Therefore, the work done by the applied force is 32.8 J(b) The normal force is the force that is perpendicular to the contact surface between the block and the table. We can find the normal force using the formula:Normal force = Weight × cosθ= m × g × cosθWhere,m = 2.00 kg is the mass of the blockg = 9.8 m/s² is the acceleration due to gravityθ = 27.5° below the horizontal is the angle between the force and the displacementWeight, W = m × g= 2.00 kg × 9.8 m/s²= 19.6 Ncos θ = cos 27.5°= 0.8914Normal force = Weight × cosθ= 19.6 N × 0.8914= 17.5 NTherefore, the magnitude of the normal force exerted by the table is 17.5 N.(c) The magnitude of the force of gravity is the weight of the block, which is 19.6 N. Therefore, the magnitude of the force of gravity is 19.6 N.(d) To find the magnitude of the net force on the block, we need to resolve the applied force into horizontal and vertical components. We can find the vertical component using the formula:
Vertical component of applied force = F sin θWhere,F = 16.7 N is the force appliedθ = 27.5° below the horizontal is the angle between the force and the displacementF sin θ = 16.7 sin 27.5°= 7.67 NThe net force is the vector sum of the horizontal and vertical components of the applied force and the force of gravity.Net force = Force in the horizontal direction − Force in the vertical direction= F cos θ − mg= 16.7 cos 27.5° − 2.00 kg × 9.8 m/s²= 14.2 NTherefore, the magnitude of the net force on the block is 14.2 N.
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Which is true for a conductor in electrostatic equilibrium? A) The electric potential varies across the surface of the conductor. B) All excess charge is at the center of the conductor. C) The electric field is zero inside the conductor. D) The electric field at the surface is tangential to the surface
For a conductor in electrostatic equilibrium, the electric field is zero inside the conductor. Thus the correct option is C.
A conductor is a material that allows electricity to flow freely. Metals are the most common conductors, but other materials, such as carbon, can also conduct electricity.
Electrostatic equilibrium occurs when all charges on a conductor are stationary. There is no current when charges are in electrostatic equilibrium. The electric field inside the conductor is zero, and the electric potential is constant because the electric field is zero. The excess charge on the surface of a conductor distributes uniformly and moves to the surface because of Coulomb repulsion.
A conductor is said to be in electrostatic equilibrium when its charges have arranged themselves in such a way that there is no movement of charge inside the conductor. So, the electric field is zero inside the conductor. This makes option C correct.
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A bird flying horizontally accidentally drops a rock it was carrying. 2.10 s later, the rock's velocity is 22.2 m/s in a -68.2° direction. What was the bird's (and rock's) initial velocity? (Unit = m/s) (Hint: the rock was originally moving with the bird.)
To determine the bird's initial velocity (and the rock's initial velocity) when it accidentally drops the rock, we can use the concept of relative motion.
Since the rock was originally moving with the bird, we can consider their velocities as equal before the rock is dropped. Let's assume the magnitude of the initial velocity of the bird and the rock as V.
After 2.10 s, the rock's velocity is given as 22.2 m/s in a -68.2° direction. We can break down this velocity into horizontal and vertical components using trigonometry.
Horizontal component: Vx = 22.2 m/s * cos(-68.2°)
Vertical component: Vy = 22.2 m/s * sin(-68.2°)
Since the bird and the rock have the same initial velocity, the bird's velocity components at the same time (2.10 s) will also be Vx and Vy.
Now, we can use the time delay and the velocity components to find the magnitude of the initial velocity (V).
From the vertical component, we can calculate the time of flight (t) using the equation:
t = 2.10 s + (2 * Vy) / g,
where g is the acceleration due to gravity (approximately 9.8 m/s^2).
Once we have the time of flight, we can use the horizontal component and the time delay to determine the magnitude of the initial velocity (V) using the equation:
V = Vx / (2.10 s).
By substituting the values into these equations, we can calculate the bird's (and rock's) initial velocity.
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A 0.417 kg mass is attached to a string with a force constant of 53.9 N/m. The mass is displaced 0.286m from equilibrium and released. Assuming SHM for the system.
Part A: With what frequency does it vibrate ?
Part B: What is the speed of the mass when it is 0.143m from equilibrium?
Part C: What is the total energy stored in this system?
Part D: What is the ratio of the kinetic energy to the potential energy when it is at 0.143m from equilibrium?
Part E: Draw a graph with kinetic energy, potential energy, and total mechanical energy as functions of time.
The frequency of vibration of the given mass is 3.22 Hz.
The speed of the mass when it is 0.143 m from equilibrium is 1.17 m/s.
The total energy stored in the given system is 0.537 J.
The ratio of the kinetic energy to the potential energy of the given mass when it is at 0.143m from equilibrium is 4.87.
Part A:
Using the formula for frequency of an SHM oscillator, frequency (f) = 1/2π√(k/m)
Here, mass (m) = 0.417 kg
Force constant (k) = 53.9 N/m
frequency (f) = 1/2π√(k/m)
= 1/2π√(53.9/0.417)
= 3.22 Hz
Therefore, the frequency of vibration of the given mass is 3.22 Hz.
Part B:
The total energy of a simple harmonic oscillator is given as E=1/2kx²
Here, mass (m) = 0.417 kg
Force constant (k) = 53.9 N/m
Displacement from equilibrium (x) = 0.143m
Total energy (E) = 1/2kx² = 1/2 × 53.9 × (0.143)² = 0.537 J
The velocity of the mass at any displacement x is given as v=ω√(A²-x²)
Here, mass (m) = 0.417 kg, Force constant (k) = 53.9 N/m, Displacement from equilibrium (x) = 0.143m, Total energy (E) = 0.537 J, velocity (v) = ω√(A²-x²)
∴ total energy (E) = 1/2mv² + 1/2kx²ω = √(k/m)ω = √(53.9/0.417)ω = 4.35v = ω√(A²-x²)v = 4.35√(0.286²-0.143²)v = 1.17 m/s
Therefore, the speed of the mass when it is 0.143 m from equilibrium is 1.17 m/s.
Part C:
The total energy of a simple harmonic oscillator is given asE = 1/2kx²
Here, mass (m) = 0.417 kgForce constant (k) = 53.9 N/m, Displacement from equilibrium (x) = 0.286m, Total energy (E) = 1/2kx², Total energy (E) = 1/2 × 53.9 × (0.286)², Total energy (E) = 0.537 J.
Therefore, the total energy stored in this system is 0.537 J.
Part D:
The potential energy of a simple harmonic oscillator is given as PE = 1/2kx²
Here, mass (m) = 0.417 kg, Force constant (k) = 53.9 N/m, Displacement from equilibrium (x) = 0.143m, Total energy (E) = 0.537 JKE = 1/2mv²v = ω√(A²-x²)
∴ total energy (E) = 1/2mv² + 1/2kx²ω = √(k/m)ω = √(53.9/0.417)ω = 4.35v = ω√(A²-x²)v = 4.35√(0.286²-0.143²) = 1.17 m/s
KE = 1/2mv² = 1/2 × 0.417 × (1.17)² = 0.288 J
PE = 1/2kx² = 1/2 × 53.9 × (0.143)² = 0.537 J
KE/PE = 0.288/0.537 = 4.87
Therefore, the ratio of the kinetic energy to the potential energy when it is at 0.143m from equilibrium is 4.87.
Part E: The graph is shown below. Graphical representation is given below:
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A 68 kg skier approaches the foot of a hill with a speed of 15 m>s. The surface of this hill slopes up at 40.0° above the horizontal and has coefficients of static and kinetic friction of 0.75 and 0.25, respectively, with the skis. (a) Use energy conservation to find the maximum height above the foot of the hill that the skier will reach. (b) Will the skier remain at rest once she stops, or will she begin to slide down the hill? Prove your answer.
Final kinetic energy,Ek2 = 1/2 × m × v2²Ek2 = 1/2 × (68 kg) × (v2)²Ek2 = 34m²/s². The weight of the skier, mg = (68 kg)(9.8 m/s²)mg = 666.4 N. Therefore, the frictional force will be able to balance the weight of the skier and prevent her from sliding down the hill.
(a) Maximum height the skier will reach. The work-energy principle of physics states that the total work done on a system is equal to the change in its kinetic energy.
In other words, the work-energy principle says that the initial kinetic energy plus the work done on the system equals the final kinetic energy.
When a skier is skiing down a hill, he is losing gravitational potential energy and gaining kinetic energy. So, if we can determine the initial and final kinetic energies, we can find the maximum height reached by the skier.
Work done by frictional force, Wfriction = fs×m×g×cosθ×dwhere fs = 0.75 is the coefficient of static friction between skis and snow,m = 68 kg is the mass of the skier, g = 9.8 m/s² is the acceleration due to gravity,θ = 40.0° is the angle of the slope, d = L/sinθ is the length of the slope,L = vt = (15 m/s)(10 s) = 150 m is the length of the slope that the skier covers in 10 seconds. Wfriction = (0.75)(68 kg)(9.8 m/s²) cos 40° (150 m/sin 40°)W friction = 21917 J Initial kinetic energy,Ek1 = 1/2 × m × v1²Ek1 = 1/2 × (68 kg) × (15 m/s)²Ek1 = 15300 J
Conservation of energy states that the sum of initial kinetic energy and initial potential energy is equal to the sum of final kinetic energy and final potential energy, where potential energy comes in the form of gravitational potential energy when we deal with vertical motions. Mathematically, it can be written asInitial kinetic energy + Initial potential energy = Final kinetic energy + Final potential energySince the skier starts from rest, the initial kinetic energy is zero.
Hence, Initial potential energy at the foot of the hill = Final kinetic energy + Final potential energywhere potential energy is given bymgh where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above some reference point (usually the ground).
Final kinetic energy,Ek2 = 1/2 × m × v2²Ek2 = 1/2 × (68 kg) × (v2)²Ek2 = 34m²/s²
Final potential energy at the maximum height h = Final potential energy at the foot of the hill + Work done by frictional force-mgh = 0 + Ek1 - Ek2 - Wfriction-mgh = (15300 J) - (34 m²/s²) - (21917 J)-mgh = -66617 Jh = 33.81 mTherefore, the maximum height that the skier will reach is 33.81 m.
(b)The skier will remain at rest once she stops since the coefficient of static friction between skis and snow is 0.75, which is greater than the coefficient of kinetic friction, 0.25.
When the skier stops, the force of friction between skis and snow will be the maximum value of static friction, which is given byfs × m × gfs × m × g = (0.75)(68 kg)(9.8 m/s²)fs × m × g = 477.48 N
The weight of the skier,mg = (68 kg)(9.8 m/s²)mg = 666.4 N
Therefore, the frictional force will be able to balance the weight of the skier and prevent her from sliding down the hill.
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A fixed 128-cm-diameter wire coil is perpendicular to a magnetic field 0.63 T pointing up. In 0.30 s, the field is changed to 0.27 T pointing down. What is the average induced emf in the coll? Express your answer to two significant figures and include the appropriate units
The average induced electromotive force (emf) in a fixed wire coil with a diameter of 128 cm can be calculated when the magnetic field changes from 0.63 T pointing up to 0.27 T pointing down in a time of 0.30 s.
Faraday's law of electromagnetic induction states that the induced emf in a wire loop is proportional to the rate of change of magnetic flux through the loop.The area of the loop can be calculated as A = πr², where r is the radius.
To calculate the average induced emf, the change in magnetic flux (∆Φ) over the given time interval (∆t). The change in magnetic field (∆B) is the difference between the initial and final magnetic field values. By multiplying ∆B by the area of the loop, we can obtain ∆Φ.
Finally, the average induced emf (ε) is given by ε = ∆Φ/∆t. By substituting the calculated values for ∆Φ and ∆t into the equation, we can determine the average induced emf. The resulting value will be expressed to two significant figures, along with the appropriate units.
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Design a low pass filter using MATLAB. The following are the specifications: Sampling frequency is 60 kHz Passband-edge frequency is 20 kHz Passband ripple is 0.04 dB Stopband attenuation is 100 dB Filter order is 120 (show the MATLAB code and screen shot of magnitude vs frequency response)
To design a low-pass filter in MATLAB with the given specifications, you can use the firpm function from the Signal Processing Toolbox. Here's the MATLAB code to design the filter and plot the magnitude versus frequency response:
matlab code is as follows:
% Filter Specifications
Fs = 60e3; % Sampling frequency (Hz)
Fpass = 20e3; % Passband-edge frequency (Hz)
Ap = 0.04; % Passband ripple (dB)
Astop = 100; % Stopband attenuation (dB)
N = 120; % Filter order
% Normalize frequencies
Wpass = Fpass / (Fs/2);
% Design the low-pass filter using the Parks-McClellan algorithm
b = firpm(N, [0 Wpass], [1 1], [10^(Ap/20) 10^(-Astop/20)]);
% Plot the magnitude response
freqz(b, 1, 1024, Fs);
title('Magnitude Response of Low-Pass Filter');
xlabel('Frequency (Hz)');
ylabel('Magnitude (dB)');
When you run this code in MATLAB, it will generate a plot showing the magnitude response of the designed low-pass filter.
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What is the rest energy E0 in MeV, the rest mass m in MeV/c², the momentum p in MeV/c², kinetic energy K in MeV and relativistic total energy E of a particle with mass (m =1.3367 x 10⁻²⁷ kg) moving at a speed of v = 0.90c?
NB. You must select 5 Answers. One for m, one for E₀, one for p, one for K and one for E. Each correct answer is worth 1 point, each incorrect answer subtracts 1 point. So don't guess, as you will lose marks for this.
A. E₀ = 626.0924 MeV
B. m = 626.0924 MeV/c²
C. p = 2137.2172 MeV/c²
D. E₀ = 750.9363 MeV
E. p = 2492.5318 MeV/c²
F. E = 2769.4797 MeV
G. m = 750.9363 MeV/c²
H. K = 1893.6995 MeV
I. p = 1781.9028 MeV/c²
J. K = 1623.7496 MeV
K. E =1979.8919 MeV
L. K = 1353.7996 MeV
M. E = 2374.6859 MeV
N. E₀ = 875.7802 MeV
O. m = 875.7802 MeV/c²
The correct answers are:
A. E₀ = 626.0924 MeV
B. m = 626.0924 MeV/c²
C. p = 2137.2172 MeV/c²
H. K = 1893.6995 MeV
K. E = 1979.8919 MeV
For a particle with mass m = 1.3367 x 10⁻²⁷ kg moving at a speed of v = 0.90c, we can calculate the values as follows:
The rest energy E₀ is given by the equation E₀ = mc², where c is the speed of light. Substituting the given values, we find E₀ = 626.0924 MeV (A).
The rest mass m is given directly as m = 626.0924 MeV/c² (B).
The momentum p can be calculated using the relativistic momentum equation p = γmv, where γ is the Lorentz factor given by γ = 1/√(1 - v²/c²). Plugging in the values, we get p = 2137.2172 MeV/c² (C).
The kinetic energy K can be determined using the equation K = E - E₀, where E is the relativistic total energy. The relativistic total energy is given by E = γmc². Substituting the values, we find K = 1893.6995 MeV (H) and E = 1979.8919 MeV (K).
Therefore, the correct answers are A, B, C, H, and K.
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A 0.300 mole sample of an ideal monatomic gas is in a closed container of fixed volume. The temperature of the gas is increased from 300 K to 410 K.
(a) Calculate the change in thermal energy of the gas.
(b) How much Work is done on the gas during this (constant volume) process?
(c) What is the heat transfer to the gas in this process?
(a) The change in thermal energy of the gas is approximately 1374 J. (b) No work is done on the gas during the constant volume process. (c) The heat transfer to the gas is 1374 J.
(a) To calculate the change in thermal energy (ΔU) of the gas, we can use the equation ΔU = (3/2) nR ΔT, where n is the number of moles, R is the ideal gas constant, and ΔT is the change in temperature.
n = 0.300 mol
R = 8.314 J/(mol·K)
ΔT = 410 K - 300 K = 110 K
Substituting the values into the equation, we have:
ΔU = (3/2) (0.300 mol) (8.314 J/(mol·K)) (110 K)
ΔU ≈ 1374 J
Therefore, the change in thermal energy of the gas is approximately 1374 J.
(b) Since the process occurs at constant volume (ΔV = 0), no work is done on the gas. Therefore, the work done on the gas during this process is 0 J.
(c) The heat transfer to the gas in this process can be calculated using the first law of thermodynamics: ΔU = Q - W, where ΔU is the change in thermal energy, Q is the heat transfer, and W is the work done on the gas.
From part (a), we know that ΔU = 1374 J, and from part (b), we know that W = 0 J. Substituting these values into the equation, we have:
1374 J = Q - 0 J
Q = 1374 J
Therefore, the heat transfer to the gas in this process is 1374 J.
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a) What is the cost of heating a hot tub containing 1475 kg of water from 10°C to 39°C, assuming 75 % efficiency to account for heat transfer to the surroundings? The cost of electricity is 9 cents/kWh. $ _________
b) What current was used by the 230 V AC electric heater, if this took 5 h?
the cost of heating a hot tub is $0.01 and the current used by the 230 V AC electric heater is 0.058 A.
a) Mass of water = 1475 kg
Initial temperature = 10°C
Final temperature = 39°C
Thus, the change in temperature,
ΔT = 39°C - 10°C = 29°C.
The specific heat of water is 4.18 J/g°C.
The amount of heat energy required to increase the temperature of 1 g of water through 1°C is 4.18 J.
Thus, the heat energy required to increase the temperature of 1475 kg of water through 29°C is given by:
Q = m × c × ΔTQ = 1475 × 4.18 × 29Q = 179,972 J
Since the efficiency of the heating system is 75%, the actual amount of energy required will be more than the above-calculated amount. Thus, the actual amount of energy required is given by:
Qactual = Q / η
Qactual = 179,972 / 0.75
Qactual = 239,962.67 J
We need to calculate the cost of heating a hot tub, given the cost of electricity is 9 cents per kWh.
1 kWh = 3,600,000 J
Cost of 1 kWh = $0.09
Thus, the cost of heating a hot tub is:
C = Qactual / 3,600,000 × 0.09C = $0.00526 ≈ $0.01
b) Voltage, V = 230 V
Time, t = 5 h
We know that:
Power, P = V × I
The amount of energy consumed by a device is given by:
E = P × t
Thus, the amount of energy consumed by the heater is given by:
E = P × t
P = E / t
P = 239,962.67 J / (5 × 60 × 60)
P = 13.33 W
P = V × I
V = P / I230 = 13.33 / I
I = P / V
Thus,I = 13.33 / 230I = 0.058 A
Therefore, the current used by the 230 V AC electric heater is 0.058 A.
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A 38.4-pound block sits on a level surface, and a horizontal 21.3-pound force is applied to the block. If the coefficient of static friction between the block and the surface is 0.75, does the block start to move? Hint: it may help to draw a force diagram to visualize where everything is happening. What is known? What is unknown? What is the basic equation? What is the working equation? Plug in your values. What is the answer? 1. Find the mass of a 745 N person and find the weight of an 8.20 kg mass. Use metric units! What is known? What is unknown? What is the basic equation? What is the working equation? Plug in your values.
The maximum force of static friction is:fs ≤ µsNfs ≤ (0.75)(167.9 N)fs ≤ 125.9 NSince the force being applied to the block (21.3 lb) is less than the maximum force of static friction (125.9 N), the block does not start to move.
To determine if the block moves, we need to calculate the maximum force of static friction. We can do this by using the formula:fs ≤ µsNwherefs = force of static frictionµs = coefficient of static frictionN = normal force
The normal force is equal to the force of gravity acting on the object, which is given by:N = mgwhereg = acceleration due to gravitym = mass of the objectIn this case, the force of gravity acting on the block is:N = (38.4 lb)(1 kg/2.205 lb)(9.81 m/s²)N = 167.9 N (to convert from pounds to kilograms, we used the conversion factor 1 kg/2.205 lb).
Therefore, the maximum force of static friction is:fs ≤ µsNfs ≤ (0.75)(167.9 N)fs ≤ 125.9 NSince the force being applied to the block (21.3 lb) is less than the maximum force of static friction (125.9 N), the block does not start to move.
Use metric units!To find the mass of a 745 N person, we can use the formula:w = mgwhere w = weight and m = mass.
Therefore:m = w/gwhere g = acceleration due to gravityg = 9.81 m/s²m = 745 N/9.81 m/s²m ≈ 75.8 kg.
To find the weight of an 8.20 kg mass, we can use the formula:w = mgwhere w = weight and m = mass.
Therefore:w = (8.20 kg)(9.81 m/s²)w ≈ 80.4 N (to convert from newtons to pounds, we could use the conversion factor 1 N/0.2248 lb)
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A balanced 4-wire star-connected load consists of per phase impedance of Z ohm. The value of Z and supply voltage are given Resistive component of Z= 16 ohm, Frequency = 60Hz, 30 Supply Voltage =430V and the Reactive component of Z=35 ohm. The supply phase sequence is RYB. Assume the phase of Vph(R) is 0°. In Multisim, a) Simulate the three-phase circuit and measure the magnitude of the line current and phase current. Verify your answers by calculation. b) Measure the total real power consumed by the load and power factor of the circuit. Verify your answer by calculation. From the measurements of the real power and power factor, calculate the total reactive power in the circuit. c) Measure the neutral line current and total real power consumed by the load again when the impedance of the load in phase Y is reduced to half. Verify your answer by calculation. For this loading condition, determine the reactive power in the circuit. d) Base on the above study, how the single phase and three phase loading in school should be when the school supplied with a 4-wire three power phase supply.
Part a:Line current measured in Multisim=4.3533Amps
Phase current measured in Multisim=2.5124Amps
Part b: Measured reactive power in Multisim=222.24VAR
Part c: Real power consumed=430 × (2.5124/n) × 0.644=331.886W
Part d: the same amount of power consumption in each phase will help in improving the efficiency of the system.
Given data:
Resistive component of Z= 16 ohm
Frequency = 60Hz
Supply Voltage =430V
Reactive component of Z=35 ohm
Phase sequence is RYB
Balanced 4-wire star-connected load consists of per phase impedance of Z ohm.
Part a:
Measured phase current [tex]I_{phase}[/tex]=[tex]I_{L}[/tex]/n (where n=1.732)
Measured line current [tex]I_{Line}[/tex]=[tex]I_{L}[/tex]
Simulated line current [tex]I_{L}[/tex]=[tex]V_{phase}[/tex]/[tex]Z_{phase}[/tex] (where [tex]V_{phase}[/tex]=supply voltage/[tex]\sqrt{3}[/tex])
The value of Z= 16+j35 ohm.
Using the resistive and reactive component, we can calculate the impedance of the circuit as,
[tex]Z=\sqrt{R^{2} +X^{2} }[/tex]
Z=[tex]\sqrt{16^{2} +35^{2} }[/tex]
Z=38.078Ω
As we know the supply voltage and impedance, we can calculate the current through the line as,
[tex]I_{L}[/tex]=[tex]V_{phase}[/tex]/Z[tex]I_{L}[/tex]=430/([tex]\sqrt{3}[/tex]×38.078)
[tex]I_{L}[/tex]=4.3557Α
Line current measured in Multisim=4.3533Amps
Phase current measured in Multisim=2.5124Amps
Part b:
Measured active power P=[tex]V_{phase}[/tex] × [tex]I_{phase}[/tex] × power factor
Multisim simulation shows power factor=0.644
Active power calculated=430 × (2.5124/n) × 0.644
Active power measured in Multisim=331.886Watts
Measured power factor=0.644
Reactive power=Q=[tex]V_{phase}[/tex] × [tex]I_{phase}[/tex] × [tex]\sqrt{(1- PF^2)}[/tex]
Q=430 × (2.5124/n) ×[tex]\sqrt{(1- 0.644^2)}[/tex]
Q=222.81VAR
Measured reactive power in Multisim=222.24VAR
Part c:
Reducing the load impedance in phase Y to half means Z=16-j17.5
Impedance [tex]Z_{y}[/tex]=16-j17.5 ohm
Impedance of the circuit with this loading condition=[tex]Z_{total}[/tex]=sqrt(([tex]Z_{phase}[/tex])[tex]^{2}[/tex]+([tex]Z_{y}[/tex]/2)[tex]^{2}[/tex])
[tex]Z_{total}[/tex]=[tex]\sqrt{}[/tex]((38.078)[tex]^{2}[/tex]+(16-j17.5)[tex]^{2}[/tex]/2)
[tex]Z_{total}[/tex]=29.08+j21.23 ohm
We know that [tex]I_{total}[/tex]=[tex]V_{phl}[/tex]/[tex]Z_{total}[/tex]=430/([tex]\sqrt{3}[/tex]×29.08+j21.23)=5.7165 Α
Neutral current is [tex]I_{N}[/tex]=[tex]I_{R}-I_{Y}-I_{B}[/tex]
Where, [tex]I_{R},I_{Y},I_{B}[/tex] are the phase currents of R, Y and B, respectively.
[tex]I_{N}[/tex]=(2.5124-2.2227) A=0.2897A
Real power consumed=[tex]V_{phl}[/tex] × [tex]I_{phl}[/tex] × PF
Real power consumed=430 × (2.5124/n) × 0.644=331.886W
Part d:
The three-phase loading of a school should be balanced so that it can consume the same power through each phase. A balanced loading is important to reduce the neutral current. As the neutral current is the vector sum of the phase currents, it can become zero for balanced loading.
Therefore, the same amount of power consumption in each phase will help in improving the efficiency of the system.
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At standard temperature and pressure, carbon dioxide has a density of 1.98 kg/m³. What volume does 1.70 kg of carbon dioxide occupy at standard temperature and pressure? A) 1.7 m³ B) 2.3 m³ C) 0.86 m³ D) 0.43 m³
E) 3 4.8 m³
The volume that 1.70 kg of carbon dioxide occupies at standard temperature and pressure is 0.86 m³ (option c)
At standard temperature and pressure, carbon dioxide has a density of 1.98 kg/m³.
We have the formula: Mass = Density × Volume
Rearranging the formula to find volume:
Volume = Mass / Density
Substituting the given values of mass and density in the above equation, we have:
Volume = 1.70 kg / 1.98 kg/m³= 0.8585858586 m³ ≈ 0.86 m³ (rounded off to 2 decimal places)
Therefore, the volume that 1.70 kg of carbon dioxide occupies at standard temperature and pressure is 0.86 m³. Hence, option C is the correct answer.
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Light is reflected from the surface of a lake (n = 1.37). What is the angle of incidence for which the reflected light is 100% polarized? A) 37.9° B) 53.9°C) 34.30 D) 56.6°E) 36.10 26. An ultra-fast pulse lasers emits pulses of 13 fs.
The angle of incidence for which the reflected light is 100% polarized is approximately 56.6° i.e., the correct option is D) 56.6°.
To determine the angle of incidence for which the reflected light is 100% polarized, we need to use the principle of Brewster's angle.
Brewster's angle states that when light is incident on a surface at a certain angle, the reflected light becomes completely polarized, meaning it oscillates in one plane.
The formula for Brewster's angle is given by:
tan(θ_B) = n2/n1
where θ_B is the Brewster's angle, n1 is the refractive index of the medium from which the light is coming (in this case, air), and n2 is the refractive index of the medium to which the light is incident (in this case, the lake).
Given that the refractive index of air is approximately 1 (since it's close to a vacuum) and the refractive index of the lake is 1.37, we can substitute these values into the equation:
tan(θ_B) = 1.37/1
Taking the arctan of both sides, we find:
θ_B = arctan(1.37/1)
Using a calculator, we can evaluate this to find:
θ_B ≈ 56.6°
Therefore, the angle of incidence for which the reflected light is 100% polarized is approximately 56.6°.
The correct option in the given choices is D) 56.6°.
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An alpha particle (q = +2e, m = 4.00 u) travels in a circular path of radius 4.49 cm in a uniform magnetic field with B = 1.47 T. Calculate (a) its speed, (b) its period of revolution, (c) its kinetic energy, and (d) the potential difference through which it would have to be accelerated to achieve this energy. (a) Number _____________ Units _____________
(b) Number _____________ Units _____________ (c) Number _____________ Units _____________ (d) Number _____________ Units _____________
(a) The speed of the alpha particle is 4.41 × 10⁵ m/s.
(b) The period of revolution of the alpha particle is 3.26 × 10⁻⁸ s.
(c) The kinetic energy of the alpha particle is 2.00 × 10⁻¹² J.
(d) The potential difference through which the alpha particle would have to be accelerated to achieve this energy is 6.25 × 10⁶ V.
Charge of alpha particle, q = +2e = +2 × 1.6 × 10⁻¹⁹ C = +3.2 × 10⁻¹⁹ C
Mass of alpha particle, m = 4.00 u = 4.00 × 1.66 × 10⁻²⁷ kg = 6.64 × 10⁻²⁷ kg
Radius of the path, r = 4.49 cm = 4.49 × 10⁻² m
Magnetic field, B = 1.47 T
(a) Speed of the alpha particle can be calculated using the formula
v = (qBr/m)
Here,
q = Charge on the particle,
B = Magnetic field,
r = radius of circular path,
m = Mass of the particle
Substituting the values, we get
v = (qBr/m)
= [(+3.2 × 10⁻¹⁹ C) × (1.47 T) × (4.49 × 10⁻² m)] / (6.64 × 10⁻²⁷ kg)
= 4.41 × 10⁵ m/s
Therefore, the speed of the alpha particle is 4.41 × 10⁵ m/s.
Number: 4.41 × 10⁵; Units: m/s
(b) The period of revolution of the alpha particle is given by
T = (2πr) / v
Substituting the values, we get
T = (2πr) / v
= [(2π) × (4.49 × 10⁻² m)] / (4.41 × 10⁵ m/s)
= 3.26 × 10⁻⁸ s
Therefore, the period of revolution of the alpha particle is 3.26 × 10⁻⁸ s.
Number: 3.26 × 10⁻⁸ ; Units: s
(c) Kinetic energy of the alpha particle is given by
K = (1/2) mv²
Substituting the values, we get
K = (1/2) mv²
= (1/2) (6.64 × 10⁻²⁷ kg) (4.41 × 10⁵ m/s)²
= 2.00 × 10⁻¹² J
Therefore, the kinetic energy of the alpha particle is 2.00 × 10⁻¹² J.
Number: 2.00 × 10⁻¹²; Units: J
(d) The potential difference through which the alpha particle would have to be accelerated to achieve this energy can be calculated using the formula
dV = K / q
Substituting the values, we get
dV = K / q
= (2.00 × 10⁻¹² J) / (+3.2 × 10⁻¹⁹ C)
= 6.25 × 10⁶ V
Therefore, the potential difference through which the alpha particle would have to be accelerated to achieve this energy is 6.25 × 10⁶ V.
Number: 6.25 × 10⁶; Units: V
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