a rigid tank of volume 2 m3 initially contains air at 0.21 bar, 290 k. a leak develops and air flows in slowly from the surroundings which are at 1.1 bar, 312 k. after a while, the tank and its surroundings come to equilibrium. what is the final temperature in the tank, in oc, and how much mass has entered the tank, in kg? neglect kinetic and potential energy effects, and assume the air is an ideal gas with constant specific heats evaluated at 300 k.

Answer:

Calcium carbonate or the calcium and magnesium double carbonate makes up the majority of the sedimentary rock known as limestone. Shell fragments, small fossils, and other fossilized detritus are frequently found in it.

Explanation:

hope it helps :)

The given statement "a conductor is any material that resists or prevents the flow of electric charge, such as electrons" is False because a conductor is a material that allows the flow of electric charge, while an insulator resists or prevents it.

Conductors have low resistance and high conductivity, which means that they allow electric charges to pass through them with minimal energy loss. Examples of good conductors are metals like copper, silver, and aluminum. In contrast, insulators are materials that resist or prevent the flow of electric charge. They have high resistance and low conductivity, which means that they obstruct the movement of electric charges, and are used to prevent electrical energy from passing where it's not desired.

In summary, a conductor is a material that allows the flow of electric charge, while an insulator resists or prevents it. Conductors have low resistance and high conductivity, while insulators have high resistance and low conductivity. Examples of conductors include metals like copper, silver, and aluminum, while insulators include materials like rubber, plastic, and glass.

Know more about Conductors here:

https://brainly.com/question/11845176

#SPJ11

The system's momentum is zero prior to the explosion since the cannon and cannonball are both at rest.. Following the explosion, the system's overall momentum is conserved. The overall momentum before and after the explosion must be the same in accordance with the law of conservation of momentum.

Between 250 and 100 m/s seems to be the most plausible range (250 m/s is equivalent to 820 feet per second).

v2 = - 2 m/s

The above equation's negative sign tells us that the gun's velocity and the bullet's velocity are diametrically opposed. Hence, the firearm will recoil.

To know more about  momentum visit:-

brainly.com/question/30487676

#SPJ1

Naoki's mass is 67 kg, due to which the force calculated to pedal is 140.7 N at acceleration of 2.1 m/s².

Newton's second law of motion is a fundamental principle in physics that describes the relationship between force, mass, and acceleration. It states that an object's acceleration is proportional to the force applied to it and inversely proportional to its mass. We can rewrite this equation to find the mass:

F = m * a

where F is the net force applied to an object, m is its mass, and a is the resulting acceleration.

To solve this problem, we can use Newton's second law of motion, which states that the force applied to an object is equal to the product of its mass and acceleration:

F = m * a

where F is the applied force, m is the object's mass, and an is the acceleration.

The second law is mathematically stated as follows:

m = F / a

Substituting the given values, we get:

m = 140.7 N / 2.1 m/s²

m = 67 kg

Naoki's mass is 67 kg.

To know more about acceleration, visit:

https://brainly.com/question/12550364

#SPJ1

If the fuel does 855 J of work on the potato, and produces 1422 J of heat, the change in internal energy of the fuel is 567 J.

According to the first law of thermodynamics, the change in internal energy of a system is equal to the heat added to the system minus the work done by the system:

ΔU = Q - W

where ΔU is the change in internal energy, Q is the heat added to the system, and W is the work done by the system.

In this case, the fuel does 855 J of work on the potato and produces 1422 J of heat. Since the potato cannon and the fuel can be considered as a closed system, the change in internal energy of the system can be calculated as:

ΔU = Q - W

ΔU = 1422 J - 855 J

ΔU = 567 J

Therefore, the change in internal energy = 567 J.

Learn more about internal energy here:

https://brainly.com/question/25737117

#SPJ11

The diagram of a thermocouple that can be used to measure the temperature of the sulfur as it cools, created with MS Word is attached.

A thermocouple is a device that consists of two different types of metal wires joined together at one end. When the junction of the two metals are heated or cooled, a voltage is produced that can be correlated to temperature. Thermocouple are commonly used to measure temperature in a variety of applications because they are rugged, inexpensive and can measure a wide range of temperatures.

To use a thermocouple to measure the temperature of molten sulfur in a beaker, you would need to insert the junction (the end where the two metal wires are joined) into the molten sulfur. The other ends of the metal wires would need to be connected to a device that can measure the voltage produced by the thermocouple. As the sulfur cools and its temperature changes, so will the voltage produced by the thermocouple. By measuring this voltage and using a reference table or equation that correlates voltage with temperature for that specific type of thermocouple, the temperature of the sulfur as it cools can be determined.

Please find attached the drawing of a thermocouple which can be used to determine the sulfur as it cools.

Learn more on temperature measuring devices here: https://brainly.com/question/30246279

#SPJ1

The Melting of ice cream is a physical change. Explosion of fire works is a chemical change. Rusting of a car is a chemical change. Making an Oragami bird and dissolving are  physical changes  

A physical change is a change in the physical properties of a substance that does not alter its chemical composition. Examples of physical changes include changes in state (solid, liquid, gas), changes in shape or size, changes in color, and changes in density or texture. Physical changes are usually reversible and do not involve the formation of new substances.

A chemical change, on the other hand, is a change in the chemical composition of a substance that results in the formation of one or more new substances with different chemical properties.

Other answers;

The circle D contains a mixture of molecules

Boiling water is not a chemical change since no new substance is formed.

Learn more about chemical change:https://brainly.com/question/23693316

#SPJ1

The electric force between the two balloons is approximately 1.04 x [tex]10^{-12}[/tex] N.

Coulomb's Law:

The electric force between two charged objects can be calculated using Coulomb's Law, which states that the magnitude of the electric force F between two charged objects is directly proportional to the product of their charges (q1 and q2) and inversely proportional to the square of the distance (r) between them:

F = k * (q1 * q2) / r²

where k is the Coulomb constant, which has a value of approximately 9.0 x [tex]10^{9}[/tex] N*[tex]m^{2}[/tex]/[tex]C^{2}[/tex].

In this case, each balloon acquires a charge of 1.2 x [tex]10^{-7}[/tex] C, so the total charge on both balloons is 2 * 1.2 x [tex]10^{-7}[/tex]C = 2.4 x [tex]10^{-7}[/tex]C. The distance between the balloons is 0.5 m.

Plugging in these values into Coulomb's Law, we get:

F = (9.0 x [tex]10^{9}[/tex] N*[tex]m^{2}[/tex]/[tex]C^{2}[/tex]) * [(1.2)²x ([tex]10^{-7}[/tex] C)²/ (0.5m)²]

Simplifying this expression gives:

F = 1.0368 x [tex]10^{-12}[/tex] N

Therefore, the electric force between the two balloons is approximately 1.04 x[tex]10^{-12}[/tex]    N.

What is magnitude?

Magnitude refers to the size or extent of something, usually measured in numerical or quantitative terms. It can refer to a physical quantity, such as length, mass, or volume, or it can refer to other measurable attributes, such as brightness, intensity, or force. In general, magnitude is a relative measure, meaning that it is typically expressed as a comparison between two or more things.

To know more about magnitude, visit:

https://brainly.com/question/14452091

#SPJ1

The length of the pipe is 0.225 m.

To solve this problem, we need to use the formula for the resonant frequencies of a pipe closed at one end,

f_n = n v / 4 L

where,

f_n = the frequency of the nth harmonic

n = the number of the harmonic (1, 2, 3, ...)

v = the speed of sound in air (which we'll assume is 343 m/s at room temperature)

L = the length of the pipe

We are given the frequencies of the 2nd and 3rd harmonics,

f_2 = 700 Hz

f_3 = 900 Hz

We can use these to find the length of the pipe,

f_2 = 2 v / (4 L)

700 Hz = 2 * 343 m/s / (4 L)

L = 0.245 m

f_3 = 3 v / (4 L)

900 Hz = 3 * 343 m/s / (4 L)

L = 0.171 m

The length of the pipe must be such that both of these equations are satisfied simultaneously. This can be done by finding the least common multiple of the denominators, which is 4L, and then solving for L,

LCM(2,3) = 6

6 L = 2 * 3 * 343 m/s / (700 Hz - 900 Hz)

L = 0.225 m

To know more about harmonics, here

brainly.com/question/24084432
#SPJ4

If the elevator is in the upward direction, the force that Yolanda exerts on the floor of the elevator is 81.792 N.

The force that Yolanda exerts on the floor of the elevator can be calculated using Newton's second law of motion, which states that force is equal to mass times acceleration:

force = mass x acceleration

In this case, Yolanda's mass is 38.4 kg, and the upward acceleration of the elevator is 2.13 m/s². So, we can plug these values into the formula:

force = 38.4 kg x 2.13 m/s²

force = 81.792 N

Since the elevator is accelerating upwards, the force that Yolanda exerts on the floor of the elevator is also upwards, so the answer is positive.

Learn more about force here:

https://brainly.com/question/13526583

#SPJ11

The impression of a leaf in soft mud may harden into a fossil over time. So, yes, the processes that preserved fossils in rock layers are still happening today.

Yes, the processes that preserved fossils in the rock layers are still happening today.What are fossils?Fossils refer to the remains of ancient plants and animals that are preserved in rock layers. They can be used to learn about the evolution of life on earth and the geological history of the planet.The processes that preserved fossils in rock layers include sedimentation, mineralization, carbonization, and trace fossilization. These processes are still happening today, and new fossils are being formed as we speak. For example, a dead animal that sinks to the bottom of a lake or ocean may be buried by sediment over time, leading to fossilization.

Learn more about  fossils here:

https://brainly.com/question/19649360

#SPJ4

The solenoid has an inductance of l. if the number of loops per unit length is increased by a factor of 5.02, the total number of loops is increased by a factor of 6.45, and the area of ​​each loop is increased by a factor of 7.26, then the inductance will be multiplied by a factor of 33.91.

L = (μn²A)/l.

Where n is the number of turns per unit length, A is the area of each turn, l is the length of the solenoid and μ is the permeability of the medium.

After the changes are made, the new values are given by,

Number of turns per unit length = 5.02n

Area of each turn = 7.26A (increased by a factor of 7.26)

Total number of turns = 6.45n

The length of the solenoid remains the same

Now, the new inductance, L' is given by,

L = (μn²A)/l

Where, n = 5.02n (number of turns per unit length increased by a factor of 5.02)

A = 7.26A (area of each turn increased by a factor of 7.26)

l = l (length remains the same)

Substituting the values of `n'`, `A'` and `l` in the above equation,

L = (μ (5.02n)² (7.26A))/l = (μ × 6.45² × 7.26 × n² × A)/l

Now, dividing the new inductance by the original inductance,

L'/L = (μ × 6.45² × 7.26 × n² × A)/l × (1/μ × n² × A)/l = 6.45² × 7.26 = 33.91

Therefore, the inductance will be multiplied by a factor of 33.91.

Learn more about solenoid inductance at https://brainly.com/question/25484149

#SPJ11

The force that allows the sunflower seed to emerge from its seed coat is: generated by the pressure from the growing embryo inside the seed coat, not any outside force.

The forces involved as a sunflower seed emerges from its seed coat are generated by the expanding plant embryo, which grows as it absorbs water and nutrients. As the embryo grows, its cells divide and become more specialized, and it increases in size, causing the seed coat to become too small to contain the growing plant.

The embryo puts pressure on the seed coat until it splits and the plant emerges. This force is due to the pressure generated by the expanding plant embryo, not any outside force. The embryo contains hormones, proteins, and other substances that cause cells to divide and specialize, which increases its size and puts pressure on the seed coat.

As it does this, the outer layers of the seed coat split, allowing the embryo to emerge. This force is not caused by gravity or any other external force. In conclusion, the force that allows the sunflower seed to emerge from its seed coat is generated by the pressure from the growing embryo inside the seed coat, not any outside force.

To know more about force refer here:

https://brainly.com/question/26115859#

#SPJ11

Answer: the answer is a

Explanation:

It will take approximately 24.3 microseconds for the voltage across the capacitor to drop to 60% of its initial value.

To determine the current in the resistor, we need to use Ohm's Law:

I = V/R

where I is the current,

V is the voltage,

and R is the resistance.

In this case, the voltage across the resistor is the same as the voltage across the capacitor, which was 6 V before the capacitor was connected to the resistor.

Therefore:

I = 6 V / 5 Ω = 1.2 A

So the current in the resistor is 1.2 A.

To determine how long it will take for the voltage across the capacitor to drop to 60% of its initial value, we can use the formula for capacitor voltage over time:

[tex]Vc(t) = V0 * e^(-t/RC)[/tex]

where Vc(t) is the voltage across the capacitor at time t,

V0 is the initial voltage across the capacitor, e is the mathematical constant e (approximately 2.71828),

t is time, R is the resistance in ohms, and C is the capacitance in farads.

We are given that the capacitance is 10 µF, or

[tex]10 * 10^-6 F.[/tex]

Assuming the resistor is still 5 Ω, we can calculate the time it takes for the voltage across the capacitor to drop to 60% of its initial value as follows:

0.6 * 6 V = 3.6 V (60% of the initial voltage)

3.6 V = 6 V * [tex]e^(-t/(5 * 10 µF))[/tex]

[tex]e^(-t/(50 µs)) = 0.6[/tex]

Taking the natural logarithm of both sides:

-t/(50 µs) = ln(0.6)

t = -50 µs * ln(0.6)

t ≈ 24.3 µs

For similar question on voltage.

https://brainly.com/question/14883923

#SPJ11

Answer:

The total energy is increasing from point 1 to point 2 because an external force is acting on the cars, pulling them upward at a constant low speed.

This force is doing work on the cars, and as a result, their gravitational potential energy is increasing.

Since the kinetic energy remains constant due to the constant low speed and friction is negligible, the total energy (which is the sum of potential energy and kinetic energy) also increases.

In summary, from point 1 to point 2:
1. An external force pulls the cars upward, increasing their height.
2. The gravitational potential energy increases due to the increased height.
3. The kinetic energy remains constant due to the constant low speed and negligible friction.
4. The total energy increases because of the increased gravitational potential energy.

For more information click here:

https://brainly.com/question/15242032?

#SPJ11

1). The current in the circuit is 0.9 A.

Using Ohm's Law, we can find the current in the circuit:

I = V/R

In this case, the resistance is 10 ohms and the voltage is 9V, so we have:

I = 9V / 10 ohms = 0.9 A

Therefore, the current in the circuit is 0.9 A.

2). The voltage in the circuit is 120.05 V.

Using Ohm's Law, we can find the voltage in the circuit:

V = I*R

In this case, the resistance is 35 ohms and the current is 3.43 A, so we have:

V = 3.43 A * 35 ohms = 120.05 V

Therefore, the voltage in the circuit is 120.05 V.

3). To find the resistance of the circuit from the graph, the resistance of the circuit is 2 ohms.

Resistance (R) = Voltage (V) / Current (I)

Since the graph shows a straight line, it means that the resistance of the circuit is constant. We can find the resistance of the circuit by calculating the slope of the line.

Slope = Rise / Run = ΔV / ΔI

Looking at the graph, we can see that the voltage increases by 4V when the current increases by 2A. Therefore:

ΔV = 4V

ΔI = 2A

Slope = ΔV / ΔI = 4V / 2A = 2 ohms

Therefore, the resistance of the circuit is 2 ohms.

4). The current pass through the circuit is [tex]I_{2}[/tex] is 2 A.

We can solve this problem by using the principle of conservation of energy. The total energy provided by the battery is equal to the sum of the energy dissipated by the resistors. Since the resistors are connected in parallel, the voltage across each resistor is the same.

The energy dissipated by a resistor is given by the formula:

E = I^2 x R x t

where E is the energy dissipated, I is the current flowing through the resistor, R is the resistance of the resistor, and t is the time for which the current flows.

For the circuit with resistor R1, the energy dissipated is:

E1 = I x R1 x t

For the circuit with resistor R2, the energy dissipated is:

E2 = I2 x R2 x t

Since the batteries are identical, the total energy provided by the battery is the same for both circuits. Therefore, we have:

E1 + E2 = I x R1 x t + I2 x R2 x t

Substituting the given values, we get:

2 x (30) x t + I2 x (45) x t = 2 x (30 + 45) x t

Simplifying, we get:

60t + 45I2t = 150t

15I2t = 90t

[tex]I_{2}[/tex] = 6 A/3 = 2 A

Therefore, the value of [tex]I_{2}[/tex] is 2 A.

To know more about current, visit:

https://brainly.com/question/31051471

#SPJ1

The Doppler method can be used to estimate the average orbital distance of a planet's orbit by measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's third law. Option c) is correct .

If a planet orbits a star, both of them revolve around their mutual center-of-mass. This center-of-mass is very close to the star's center since stars are much more massive than planets. As a result, if the star and planet orbit each other, they appear to move in small circles or ellipses around a fixed point.In the Doppler method, astronomers observe the motion of a star, which can reveal the presence of an exoplanet.

When a planet orbits a star, the star moves slightly as a result of the gravitational tug of the planet. This motion causes the star's spectrum to shift slightly towards longer wavelengths (redshift) and shorter wavelengths (blueshift) as the star moves away from and towards us respectively. The size of this shift depends on the mass of the planet and its orbital distance from the star.

By measuring the size of these shifts, astronomers can infer the presence of an exoplanet and estimate its mass and orbital distance. Hence option c) Is correct ,

To know more about Doppler method refer here :

https://brainly.com/question/1330077

#SPJ11

The activity reading at 6 meters from the source as observed by the technologist will be  5mR/hr

The activity reading at 6 meters from the source can be calculated using the inverse square law, which states that the radiation intensity is inversely proportional to the square of the distance from the source. Therefore, the activity reading at 6 meters from the source can be calculated as follows:

Activity at 6m = (Distance at 1st measurement / Distance at 2nd measurement)² x Activity at 2m

Activity at 6m = (2m / 6m)² x 45mR/hr

Activity at 6m = (1/9) x 45mR/hr

Activity at 6m = 5mR/hr

Therefore, the activity reading at 6 meters from the source is 5mR/hr. This calculation demonstrates that as the distance from a radiation source increases, the radiation intensity decreases significantly, which is a fundamental principle in radiation safety.

It is essential to maintain appropriate distances from radiation sources and use appropriate protective equipment to minimize exposure to ionizing radiation.

To know more about inverse square law, refer here:

https://brainly.com/question/30562749#

#SPJ11

Answer: All matter is made up of very small particles called atoms.

Explanation:Atoms are the basic building blocks of ordinary matter

The altitude must the pilot begin to pull out of the dive to avoid crashing into the sea if he can withstand an acceleration of 8.0 g 's without blacking out is 19000 feet.

The acceleration experienced by the pilot is given by the formula:a = g - (g²)/(2gh+a) where a = acceleration g = acceleration due to gravity h = altitude a = acceleration. The maximum acceleration that a person can withstand is approximately 8 g's, which is the value of acceleration that the pilot can withstand without blacking out. So, by putting the given value of acceleration into the above formula, we get 8g = g - (g²)/(2gh+a)

Multiplying throughout by (2gh+a) we get: 16gh+8ga = 2gh - g².Dividing throughout by g and rearranging, we get: 2gh/g + g/8a = 1h/g + g/16a = 1/2.By substituting the given values:g = 9.8 m/s²a = 8gh/g = h.The value of h is found to be:h = 5.5 km = 5,500 m = 18,000 feet. Therefore, the altitude must the pilot begin to pull out of the dive to avoid crashing into the sea if he can withstand an acceleration of 8.0 g 's without blacking out is 19000. Answer: 19,000 feet.

More on altitude: https://brainly.com/question/15222094

#SPJ11

The constant angular acceleration of the wheel is: 33.80 rad/s²`.

To determine the constant angular acceleration of a wheel, you can use the formula for angular acceleration which is given as: (final angular velocity - initial angular velocity) divided by time.
α= (ωf-ωi)/t    

The initial angular velocity is zero since the wheel starts from rest, so it can be assumed as zero.
Then, you can substitute the given final angular velocity and the time taken to reach that velocity in the formula to calculate the angular acceleration of the wheel.
Once the values are substituted, simplification can be done to obtain the numerical value of the angular acceleration in radians per second squared.
In the given example, the final angular velocity is 98.9 rad/s and the time taken to reach that velocity is 2.93 seconds. Substituting these values in the formula:
α= (98.9 rad/s - 0)/2.93s`Simplifying gives`α= 33.80 rad/s²`

To learn more about "Angular acceleration" here:

https://brainly.com/question/29428475#

#SPJ11

As a result, the combined ultimate velocity of the male and female skaters following the throw is 5.27 m/s.

The object's initial velocity can be calculated by dividing the total distance travelled by the amount of time it took the object to travel that distance. In the formula V = d/t, V is the speed, d the distance, and t the time.

Prior to the throw, the system's momentum is given by: p1 = m1v1 + m2v2.

replacing the specified values:

p1 = (82 kg)(7.4 m/s) + (48 kg)(0 m/s)

p1 = 607.6 kg m/s

Following the throw, the system's momentum is:

p2 = (82 kg)v' + (48 kg)(8.6 m/s)

where v' is the combined final speed of the male and female skaters. We may equate p1 and p2 using the conservation of momentum principle:

p1 = p2

(82 kg)(7.4 m/s) = (82 kg)v' + (48 kg)(8.6 m/s)

Simplifying and solving for v', we get:

v' = [ (82 kg)(7.4 m/s) - (48 kg)(8.6 m/s) ] / 82 kg

v' = 5.27 m/s

To know more about velocity visit:-

https://brainly.com/question/17127206

#SPJ1

Length of the wire is approximately 1.245 meters.

A more detailed explanation of the answer.

To find the length of the wire, we can use the formula for the magnetic force on a current-carrying wire in a magnetic field:

F = I * L * B * sin(θ)

where F is the force (30 N), I is the current (4.0 A), L is the length of the wire (unknown), B is the magnitude of the magnetic field, and theta is the angle between the current and magnetic field.

First, we need to find the magnitude of the magnetic field B:

B = √(5.0² + 7.0²) = √(25 + 49) = √74 T

Since the current is along the x-axis and the magnetic field has components in both the x and y directions, the angle theta between the current and magnetic field can be calculated using:

cos(theta) = (Bx / B) = (5.0 / √74)

So, theta = arccos(5.0 / √74)

Now we can plug in the values into the formula for the magnetic force:

30 N = 4.0 A * L * √74 T * sin(arccos(5.0 / √74))

Rearrange to solve for L:

L = (30 N) / (4.0 A * √74 T * sin(arccos(5.0 / √74)))

Now, calculate L:

L ≈ 1.245 m

So, the length of the wire is approximately 1.245 meters.

Learn more about magnetic force.

brainly.com/question/3160109

#SPJ11

The time taken for a ping pong ball to fall from a height of 324 meters, with no air resistance, is approximately 8.03 seconds.

Air resistance is the force of friction that acts on any object as it moves through the air. As a result, an object's velocity decreases. As a result, the height of the tower, the gravitational constant, and the absence of air resistance are all taken into account in order to calculate the time it takes for the ping pong ball to hit the ground.Using the following equation, the time it takes for a ping pong ball to fall from a height of 324 meters, with no air resistance, can be calculated:

t=√2h/g

Where:t= time taken to fall, h= height, g= gravitational constant (9.8 m/s²)

Using the values given in the problem,

t=√2(324)/9.8

t= 8.03 seconds

Hence, the time taken for a ping pong ball to fall from a height of 324 meters, with no air resistance, is approximately 8.03 seconds.

Learn more about "air resistance" at: https://brainly.com/question/30733938

#SPJ11

The child must make 1.5 revolutions around the merry-go-round in order for it to make one full revolution.

The child must make 1.5 revolutions around the merry-go-round in order for it to make one full revolution. Using the conservation of angular momentum, we can calculate the angular velocity of the system and the time it takes for the child to make one revolution around the merry-go-round. The initial angular momentum of the stationary system is zero, but when the child walks around the edge, they increase the rotational inertia of the system. Solving for the final angular velocity, we get ωfinal = -1.675ωinitial. Then, solving for the time it takes for the child to make one revolution, we get t = 2π / ωinitial. Setting the time for the child's revolution equal to the time for the merry-go-round's revolution, we can solve for the number of revolutions the child must make, which is 1.5.

learn more about angular velocity here:

https://brainly.com/question/29557272

#SPJ4

Explanation:

The cutoff (threshold) frequency for a metal surface that has a work function of 5.42 eV is given by the formula f0 = (φ/h) × (1/e),

where φ is the work function of the metal, h is the Planck's constant, and e is the charge of an electron.1

eV = 1.60 × 10-19 J, h = 6.626 × 10-34 J ∙ sHere,φ = 5.42 eV = 5.42 × 1.60 × 10-19 Jh = 6.626 × 10-34 J ∙ se = 1.60 × 10-19 C

Thus, the cutoff frequency is:f0 = (φ/h) × (1/e) = (5.42 × 1.60 × 10-19 J)/(6.626 × 10-34 J ∙ s) × (1/1.60 × 10-19 C)≈ 1.31 × 1015 Hz

Therefore, the cutoff (threshold) frequency for a metal surface that has a work function of 5.42 eV is 1.31 × 1015 Hz. The answer is A) 1.31 × 1015 Hz.

To know more about Threshold frequency here :

https://brainly.com/question/726252

#SPJ11

Answer:

B

Explanation:

the other ones don't really make sense

The scenario that correctly illustrates heat is:" A cold person's hands get warmer by holding a rock that has been sitting in the sun." The correct option is B.

Heat is a form of energy that is transferred from one object or system to another as a result of a difference in temperature. Heat is a type of thermal energy, which is the total energy associated with the random motion of atoms and molecules within a substance.

Heat can be transferred in three ways: conduction, convection, and radiation. Conduction is the transfer of heat energy through a material or between two materials in contact. Convection is the transfer of heat energy by the movement of fluids, such as air or water, and radiation is the transfer of heat energy through electromagnetic waves, such as light or infrared radiation.

Here in this question,

In option A), a cold person sitting in a sauna with a temperature of 105° F would actually become warmer due to the transfer of heat from the sauna to the person's body. so it is incorrect.

In option C), the ice in a cold glass of water does not melt because the water is below the freezing point of water. This is an example of a lack of heat transfer. so it is not relevant to the question.

In option D), the bathtub full of hot water does not get warmer in a cold room because heat energy is lost to the colder surroundings, causing the water to cool down. so it is incorrect.

Therefore, option B i.e" cold person's hands get warmer by holding a rock that has been sitting in the sun." is correct.

To know more about convection click:

https://brainly.com/question/30801918

#SPJ5

The cubic term increases the work needed to compress an ideal spring by: 66.67 percent.

The work required to compress an ideal spring is given by the equation W = (1/2)kx².
The cubic term, which is usually ignored in the linear force-extension equation, is introduced into the equation for work done because the spring's potential energy increases non-linearly as it is compressed.

The equation for work done on an ideal spring that takes into account the cubic term is:
W = (1/2)kx² + (1/3)kx³.From the above equation, it can be seen that the work done is increased by the cubic term.

The question is asking by what percentage the cubic term increases the work done over what would be needed to compress an ideal spring without the cubic term.
Here is the calculation: If we take out the cubic term from the above equation, we get W = (1/2)kx².
So the difference is (1/3)kx³, which is the contribution of the cubic term to the work done.
The percentage increase is given by:(0.333kx³ / 0.5kx²) x 100% = 66.67%

To know more about "Ideal spring" refer here:

https://brainly.com/question/26923303#

#SPJ11