Question 1

A Hooke's law spring is compressed 12.0 cm from equilibrium and the potential energy stored is 36.0 J. What is the spring constant in this case?

Accepted Answer

The answer of A Hooke's law spring is compressed 12.0...

Question 2

When a Hooke's law spring is stretched a distance 3x, how much is the increase in energy stored in it from when it was stretched a distance x? Give your answer in terms of a multiple of the energy stored in the spring when it is stretched a distance x.

Accepted Answer

The energy stored in a spring is proportional to the square of the displacement. So when the spring is stretched a distance 3x, the energy stored in it is (3x)^2 = 9x^2 times the energy stored when it is stretched a distance x. Therefore, the increase in energy stored is 9-1=8 times the energy stored when it is stretched a distance x. Thus the answer is D, as it states that the increase is 9 times as much, which is the same as saying the energy stored is 8 times as much.

Question 3

Which of the following is an example of a nonconservative force?

Accepted Answer

Friction is a nonconservative force because it dissipates mechanical energy as heat, unlike conservative forces like gravity and spring force which conserve mechanical energy.

Question 4

A 50-N crate is pulled up a 5.0-m inclined plane by a worker at constant velocity. If the plane is inclined at an angle of 37 $\degree$to the horizontal and there exists a constant frictional force of 20 N between the crate and the surface, what is the force applied by the worker?

Accepted Answer

The answer of A 50-N crate is pulled up a...

Question 5

Which of the following is that form of energy associated with an object's location in a conservative force field?

Accepted Answer

Potential energy is the form of energy associated with an object's location in a conservative force field. It is the energy that an object possesses due to its position or arrangement of its parts. It can be calculated as the work done by a conservative force in bringing an object from one position to another, and is a scalar quantity. Thermal energy is the energy associated with the temperature of an object, bio-chemical energy is the energy stored in chemical bonds of molecules, and kinetic energy is the energy possessed by an object in motion.

Question 6

The SI units for k, the spring constant, are equivalent to:

Accepted Answer

The spring constant k has units of force per unit length (N/m), which is equivalent to kg/s².

Question 7

By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 4.00 cm to 8.00 cm?

Accepted Answer

The energy stored in a Hooke's law spring is given by the formula E = (1/2) kx^2, where k is the spring constant and x is the displacement from the equilibrium position. When the stretch is increased from 4.00 cm to 8.00 cm, the displacement (x) increases by a factor of 2. Therefore, the energy stored increases by a factor of (2)^2 = 4. This is equivalent to a percentage increase of 300% (i.e., the energy stored is quadrupled). Thus, the correct answer is C.

Question 8

A 2000-kg ore car rolls 50.0 m down a frictionless 10.0 $\degree$ incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 2.00 m?

Accepted Answer

The answer of A 2000-kg ore car rolls 50.0 m...

Question 9

In a problem using energy considerations to solve for the speed of a ball thrown from the top of a building when it strikes the ground below, where should the potential energy have its zero value?

Accepted Answer

The choice of the zero level for potential energy is arbitrary in physics problems because only changes in potential energy are physically meaningful. What matters is the difference in potential energy between two points, not the absolute values. Therefore, any of these choices could be used without affecting the outcome of the problem, as long as the calculations are consistent with the chosen reference point.

Question 10

An amount of work equal to 3.0 J is required to compress the spring in a spring-gun. What is the "launch speed" of a 15 g marble?

Accepted Answer

The answer of An amount of work equal to 3.0...

Question 11

A Hooke's law spring is mounted horizontally over a frictionless surface. The spring is then compressed a distance d and is used to launch a mass m along the frictionless surface. What compression of the spring would result in the mass attaining double the kinetic energy received in the above situation?

Accepted Answer

The kinetic energy received by the mass is proportional to the square of the compression distance of the spring. To double the kinetic energy, you need to increase the compression distance by the square root of 2, which is approximately 1.41.

Question 12

A pendulum consists of a mass m suspended from a string of length L. When the pendulum is swinging, how much greater is the mass's potential energy when the string is displaced from the vertical by the angle  than when the mass is at the lowest position?

Accepted Answer

The answer of A pendulum consists of a mass m...

Question 13

Which of the following is that form of energy associated with an object's motion?

Accepted Answer

Kinetic energy is the energy associated with an object's motion, which depends on its mass and velocity. Potential energy is stored energy due to an object's position or configuration, thermal energy is the internal energy of a system due to the movement of particles, and bio-chemical energy is energy stored in molecules and released in chemical reactions.

Question 14

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest speed just as it impacts with the ground?

Accepted Answer

The answer of Three different-mass projectiles are launched at different...

Question 15

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest kinetic energy just as it impacts with the ground?

Accepted Answer

The answer of Three different-mass projectiles are launched at different...

Question 16

Which of the following is not true about potential energy?

Accepted Answer

Potential energy is a scalar quantity, which means it has magnitude but not direction. It is related to position and is considered stored energy. Therefore, all of the other choices are true statements about potential energy.

Question 17

A Hooke's law spring is compressed 12.0 cm from equilibrium, and the potential energy stored is 36.0 J. What compression (as measured from equilibrium) would result in 100 J being stored in this case?

Accepted Answer

The answer of A Hooke's law spring is compressed 12.0...

Question 18

A Hooke's law spring is mounted horizontally over a frictionless surface. The spring is then compressed a distance d and is used to launch a mass m along the frictionless surface. What compression of the spring would result in the mass attaining double the speed received in the above situation?

Accepted Answer

The answer of A Hooke's law spring is mounted horizontally...

Question 19

A worker pushes a sled with a force of 40 N over a level distance of 6.0 m. If a frictional force of 16 N acts on the wheelbarrow in a direction opposite to that of the worker, what total work is done on the wheelbarrow?

Accepted Answer

The answer of A worker pushes a sled with a...

Question 20

A spring with spring constant k is used to launch a mass m up a frictionless inclined plane having angle of elevation  . What is the maximum height reached above the starting elevation of the mass during the motion of the mass if the spring is compressed a distance d before launch?

Accepted Answer

The answer of A spring with spring constant k is...

Quiz 6: Work and Energy

A Hooke's law spring is compressed 12.0 cm from equilibrium and the potential energy stored is 36.0 J. What is the spring constant in this case?

When a Hooke's law spring is stretched a distance 3x, how much is the increase in energy stored in it from when it was stretched a distance x? Give your answer in terms of a multiple of the energy stored in the spring when it is stretched a distance x.

Which of the following is an example of a nonconservative force?

A 50-N crate is pulled up a 5.0-m inclined plane by a worker at constant velocity. If the plane is inclined at an angle of 37 $\degree$ to the horizontal and there exists a constant frictional force of 20 N between the crate and the surface, what is the force applied by the worker?

Which of the following is that form of energy associated with an object's location in a conservative force field?

The SI units for k, the spring constant, are equivalent to:

By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 4.00 cm to 8.00 cm?

A 2000-kg ore car rolls 50.0 m down a frictionless 10.0 $\degree$ incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 2.00 m?

In a problem using energy considerations to solve for the speed of a ball thrown from the top of a building when it strikes the ground below, where should the potential energy have its zero value?

An amount of work equal to 3.0 J is required to compress the spring in a spring-gun. What is the "launch speed" of a 15 g marble?

A pendulum consists of a mass m suspended from a string of length L. When the pendulum is swinging, how much greater is the mass's potential energy when the string is displaced from the vertical by the angle than when the mass is at the lowest position?

Which of the following is that form of energy associated with an object's motion?

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest speed just as it impacts with the ground?

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest kinetic energy just as it impacts with the ground?

Which of the following is not true about potential energy?

A Hooke's law spring is compressed 12.0 cm from equilibrium, and the potential energy stored is 36.0 J. What compression (as measured from equilibrium) would result in 100 J being stored in this case?

A Hooke's law spring is mounted horizontally over a frictionless surface. The spring is then compressed a distance d and is used to launch a mass m along the frictionless surface. What compression of the spring would result in the mass attaining double the speed received in the above situation?

A worker pushes a sled with a force of 40 N over a level distance of 6.0 m. If a frictional force of 16 N acts on the wheelbarrow in a direction opposite to that of the worker, what total work is done on the wheelbarrow?

A spring with spring constant k is used to launch a mass m up a frictionless inclined plane having angle of elevation . What is the maximum height reached above the starting elevation of the mass during the motion of the mass if the spring is compressed a distance d before launch?

Quiz 6: Work and Energy

A Hooke's law spring is compressed 12.0 cm from equilibrium and the potential energy stored is 36.0 J. What is the spring constant in this case?

When a Hooke's law spring is stretched a distance 3x, how much is the increase in energy stored in it from when it was stretched a distance x? Give your answer in terms of a multiple of the energy stored in the spring when it is stretched a distance x.

Which of the following is an example of a nonconservative force?

A 50-N crate is pulled up a 5.0-m inclined plane by a worker at constant velocity. If the plane is inclined at an angle of 37 °\degree° to the horizontal and there exists a constant frictional force of 20 N between the crate and the surface, what is the force applied by the worker?

Which of the following is that form of energy associated with an object's location in a conservative force field?

The SI units for k, the spring constant, are equivalent to:

By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 4.00 cm to 8.00 cm?

A 2000-kg ore car rolls 50.0 m down a frictionless 10.0 °\degree° incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 2.00 m?

In a problem using energy considerations to solve for the speed of a ball thrown from the top of a building when it strikes the ground below, where should the potential energy have its zero value?

An amount of work equal to 3.0 J is required to compress the spring in a spring-gun. What is the "launch speed" of a 15 g marble?

A pendulum consists of a mass m suspended from a string of length L. When the pendulum is swinging, how much greater is the mass's potential energy when the string is displaced from the vertical by the angle than when the mass is at the lowest position?

Which of the following is that form of energy associated with an object's motion?

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest speed just as it impacts with the ground?

Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest kinetic energy just as it impacts with the ground?

Which of the following is not true about potential energy?

A Hooke's law spring is compressed 12.0 cm from equilibrium, and the potential energy stored is 36.0 J. What compression (as measured from equilibrium) would result in 100 J being stored in this case?

A Hooke's law spring is mounted horizontally over a frictionless surface. The spring is then compressed a distance d and is used to launch a mass m along the frictionless surface. What compression of the spring would result in the mass attaining double the speed received in the above situation?

A worker pushes a sled with a force of 40 N over a level distance of 6.0 m. If a frictional force of 16 N acts on the wheelbarrow in a direction opposite to that of the worker, what total work is done on the wheelbarrow?

A spring with spring constant k is used to launch a mass m up a frictionless inclined plane having angle of elevation . What is the maximum height reached above the starting elevation of the mass during the motion of the mass if the spring is compressed a distance d before launch?

A 50-N crate is pulled up a 5.0-m inclined plane by a worker at constant velocity. If the plane is inclined at an angle of 37 $\degree$ to the horizontal and there exists a constant frictional force of 20 N between the crate and the surface, what is the force applied by the worker?

A 2000-kg ore car rolls 50.0 m down a frictionless 10.0 $\degree$ incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 2.00 m?