17. An ambulance at rest blows a siren of frequency 700 Hz. A vertical reflecting board
which is moving at constant velocity 4 ms¹ towards the ambulance. How many beats
per 5 seconds can be heard by the driver in the ambulance?
(The speed of sound is 350 ms ¹)
Answer:
In this case the board is moving towards the observer so the board will receive the frequency as a moving observer
The board then emits the sound received and becomes a moving source according to the driver in the ambulance
f' = f (V + Vo) / V where V is the speed of sound and f' is the frequency received by the moving board
Now the board becomes a moving source and
f' = f (V / (V - Vs) and V is again the speed of sound
Combining these equations we get
f = (V + Vo) / (V - Vs) = 700 (350 + 4) / (350 - 4) = 716 / s
The driver would hear 16 beats / sec
Note: one can do these separately
f' = 700 * (350 + 4) / 350 = 708 frequency received for moving observer
f' = 708 * 350 / (350 - 4) = 716 / sec moving source stationary observer
Every 5 sec one would hear 5 * 16 = 80 beats
A crane lifts a steel grider in 45s.it required the crane to do 8750000 j of work .how much power did the crane use
Answer:
[tex]194.44kw[/tex]
Explanation:
[tex]power = \frac{workdone}{time \: taken} [/tex]
[tex] p = \frac{8750000}{45} [/tex]
[tex]p = 194444.44watt[/tex]
[tex]p = 194.44kw[/tex]
State 'True' or 'False'. Rewrite the false statements correctly.
1.The body at terminal velocity will have less weight than the drag force.
2.The line of gravity is always within the base of support of the body in stable equilibrium
3.The force that accelerates a falling body is the force of friction.
Answer:
1. False
Corrected statement: The body at terminal velocity will have equal weight to the drag force.
2. True
3. False
Corrected Statement: The force that accelerated a falling body is the force of gravity.
Explanation:
1. This statement is false. Terminal velocity occurs when the magnitude of the drag force is equal to the magnitude of the force of gravity. This causes zero net force, meaning zero accleration and the object is at its maximim (terminal) velocity.
2. True - if a body is in stable equilibrium, the line of grvaity must be within the base of support.
3. A falling body towards the center of a planet is caused by the force of gravity.
A 22 ohm resistor and a 33 ohm resistor are connected in series and placed across a 120-v potential differance
a. What is the equivalent resistance of the circuit?
b. What is the current in the circuit?
c what is the voltage drop across each resistor?
d what is the voltage drop across the two resistors together?
Answer:
Explanation:
Part A
Resistances in Series Add
Rt = R1 + R2
Rt = 33 + 22
Rt = 55 ohms
Part B
Current is found by using ohms law
I = E/R
E = 120 volts
R = 55 ohms
I = 120/55
I = 2.18
Part C
a)E = I * R
E = ?
I = 2.18
R = 22 ohms
E = I * R
E = 2.18 * 22
E = 48 volts when I is not rounded in Part B
b)E = I * R
E = ?
I = 2.1818...
R = 33
E = 2.181818... * 33
E = 72 when the repeating decimal is allowed to repeat.
Part D
The total voltage drop across both resistors adds
E = 72 + 48
E = 120 Volts
a graph for horizontal position vs gravitational potential energy represents which of the following
(a) represent the slope of a track
(b) represent opposite of slope of track
(c) a linear relationship
Answer:
this may not be what you're looking for but here you go
Explanation:
A horizontal line means the object is not changing its position - it is not moving, it is at rest. A downward sloping line means the object is returning to the start. Speed-Time graphs are also called Velocity Time graphs. Speed-Time graphs look much like Distance-Time graphs.
A disk-shaped platform has a known rotational inertia. The platform is mounted on a fixed axle and rotates in a horizontal plane, as shown above. A student wishes to determine the frictional torque exerted on the platform by the axle as the platform rotates. The student has access to equipment that would usually be found in a school physics laboratory.
The quantities that can be measured from the disk-shaped platform include mass, radius for moment of inertia, and rotational frequency for omega.
What is Inertia?It should be noted that inertia simply means the property of all matter by which they tend to remain in constant and uniform motion unless they're acted by an external force.
In this case, the quantities that can be measured from the disk-shaped platform include mass, radius for moment of inertia, and rotational frequency for omega.
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Analyze: How do the positions of the hot and cold water affect th
e speed of convection?
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Consider a uniform electric field in the z-direction. The potential is a constant
(a) for any x for a given z
(b) for any y for a given z
(c) on the x-y plane for a given z
(d) all of these
All of the above
As it's given that
A uniform electric field in the z directionMeans the plane it's perpendicular to it xy plane.
It's for any x and any yHence all are correct
Answer:
(d) all of theseExplanation:
It is given that the electric is uniform in the z-direction.
Therefore,
For any x for a given z, the potential will be constantFor any y for a given z, the potential will be constantOn the x-y plane for a given z, the potential will be constantAll of them are correct, so the correct option is dDescribe two ways that venus does not follow the patterns of the other inner planets.
Following are the ways that Venus does not follow the patterns of the other inner planets because Venus lacks life and water oceans, like does Earth.
What are inner planet?Mercury, Mars , Earth,and Venus and are known as inner planets because their surfaces are compact and rocky, similar to Earth's terra firma.
Venus and the other inner planet are pretty different as well. Following are the ways that Venus does not follow the patterns of the other inner planets are;
1. Venus has an atmosphere that is nearly 100 times thicker than Celestial bodies with extremely heated surface temperatures.
2. Venus lacks life and water oceans, like does Earth.
3. In comparison to Earth and the other planets, the Venus rotates backwards.
Hence, Venus does not follow the patterns of the other inner planets.
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Continuing from the previous question, the coefficient of kinetic friction between block A and the tabletop is closest to:
A kinetic friction simply means the force that is in the opposite direction to the body's movement.
What is kinetic friction?Your information is incomplete. Therefore, an overview of kinetic friction will be given. Kinetic friction simply means an inhibitory force that's present when an object begins to move.
In this case, a kinetic friction simply means the force that is in the opposite direction to the body's movement that slides with respect to the surface.
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In one to two sentences, describe the relationship between harmonics and resonance frequency in a piano?
The harmonic frequency is the frequency of the harmonic motion. Whereas the resonance frequency is the frequency at which the oscillation achieves its highest point.
What is resonance frequency?Mechanical systems and charged particles all have a frequency that they vibrate at. this frequency is referred to as the resonance frequency or natural frequency.
When the matching vibrations of another item enhance the amplitude of an object's oscillations, this is known as resonance.
A harmonic is a wave with a frequency that is a positive integer multiple of the original wave's frequency.
Whereas the resonance frequency is the frequency at which the oscillation achieves its highest point.
The fundamental frequency is the lowest resonant frequency, while the overtones are the higher resonant frequencies. Harmonics are all resonant frequencies that are multiples of the fundamental.
Hence we may deduce that harmonics and resonance frequency have a direct relationship.
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A box is at rest on the floor. The coefficient of static friction between the box and the floor is . A horizontal force of is applied to the box. Will it move?
Answer:
yes, it will move but slowly
Explanation:
The friction force between the box and the floor don't stop it from moving.... but it slow down its speed
What is the net force and direction the box will move in ?
Answer:
5 Newton to right direction
Explanation:
5N to the right will be vanishes with 5N to the left..... then the another 5N to right will be the force that move the box
List each of the 50 states and their state capitals.
Answer:
I would type it out, but the system says I can't..so I hope this helps : )
Explanation:
What is equilibrium
pls answer i know but need to confirm
Answer:
a state in which opposing forces or influences are balanced.
Explanation:
Answer: A state of balance between two forces
Explanation: hope this helps!
Why do asteroids and comets differ in composition?.
Asteroids are made up of metals and rocky material, while comets are made up of ice, dust and rocky material. Both asteroids and comets were formed early in the history of the solar system about 4.5 billion years ago.
A tuning fork is struck and produces a sound. The wavelength of this
sound is 2.5 m and the period of this sound is 0.25 s. Find the
frequency of the sound wave and the speed of the wave.
Answer:
Speed= 10meters per second, Frequency = 4hz
Explanation:
First we need to find the frequency of the wave. The formula for frequency is: f (frequency) = 1 / T (period). This means we need to convert the period into seconds and then use it as a denominator with one on the numerator.
Since the period is 0.25,
1/0.25= 4hz
Now, we just need to multiply the frequency with the wavelength
4hzx2.5= 10
= 10 meters per second
Did a large terrestrial planet ever form in the region of the asteroid belt?.
Which form of electromagnetic radiation produces the warmth one feels when standing in front of a campfire?.
Why do some quasars have red shifts greater than 1?.
Answer:
They are very distant.
Explanation:
With relativistic red shifts that take into account dilation of space-time, as Einstein predicted.
Hello people ~
A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The potential at the centre of the sphere is
(a) 0 V
(b) 10 V
(c) Same as at point 5 cm away from the surface
(d) Same as at point 25 cm away from the surface
Answer:
10V
Explanation:
Hollow sphere means two spherical surfaces inside
So charge on the surface =Charge at any point in sphere i.e voltage remains constant.
So
potential at centre=Potential at surface=10V
Option B is correct
What is the discharge of a stream that is one meter deep, two meters wide, and has a water flow of 5 meters per second
Answer:
10 m^3 /s
Explanation:
1 m X 2 m X 5 m /s = 10 m^3/s
Which statement below could be used as evidence to support the claim that using nuclear energy to produce electricity is better than using fossil fuels?
A. Radioactive waste can be stored deep underground in order to minimize the risk of exposure to dangerous radiation.
B. Nuclear energy does not produce harmful pollution.
C. Nuclear does not produce greenhouse gases that contribute to global warming.
D. Nuclear energy is cheaper than using fossil fuels.
Answer:
C
Explanation:
C would make the most sense because the problem with fossil fuels is the fact that it emits greenhouse gases that warm up the earth over a long period of time as the climate has changed because of it.
Two objects are placed on a scale so that it balances. One object weighs 5 N and is placed 0.5 m from the fulcrum of the scale. The other object is placed 1 m from the fulcrum. How heavy is the other object?
The weight of the other object placed 1 m from the fulcrum that balances the other object is 2.5 N.
Principle of moment
The weight of the second object is determined by applying principle of moment as shown below;
take moment about the pivot,
sum of clockwise moment = sum of anticlockwise moment
F₁r₁ = F₂r₂
5 x 0.5 = F₂ x 1
2.5 N = F₂
Thus, the weight of the other object placed 1 m from the fulcrum that balances the other object is 2.5 N.
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How does the energy of a photon emitted by a higher-wattage red light bulb compare to the energy of a photon emitted by a lower-wattage red light bulb
Answer:
The energy of the photon from the higher-wattage bulb is equal to the energy of the photon from the lower-wattage bulb.
Explanation:
Sound travels slowest through what temperature of water?.
Answer:
20 degrees.
Explanation:
this is my answer hope that I will help you
Hello people ~
When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges separated by a distance
(a) increases K times
(b) remains unchanged
(c) decreases K times
(d) increases K^-1 times
Explanation:
In di electric medium
The force is
[tex]\sf F_{dE}=\dfrac{1}{4K\pi\epsilon}\dfrac{q_1q_2}{R^2}[/tex]So the force on air is decreased k times
Option C is correct
What is the fundamental frequency of a
guitar string when the speed of waves on
the string is 115 m/s and the effective string
length is 0.720 m?
Answer quickly if possible
Answer:
dk
Explanation:
sorry jus rlly not that smartWhich term best describes the form of beryllium shown
Answer:
✓ Ion
Explanation:
Which term BEST describes the form of beryllium shown? Protons=4 Neutrons=5 Electrons=2
✓ Ion
Describe what voltage is
Answer:
electrical 'pressure' measurement
Explanation: