Chapter 11, Problem 82A

(a)

To determine

A specific example that illustrates the given conditions.

Answer to Problem 82A

Example of billiard ball.

Explanation of Solution

Given:

It is given that when a work is done on the system, there will be an increase in kinetic energy while the potential energy remains unchanged.

The system consists of the billiard ball table itself. When a billiard ball is pushed across the table, its kinetic energy changes due to the force but potential energy remains the same. As the ball changes its state from rest to motion, all the effort was done by the external force only.Hence, no change in its potential energy but kinetic energy will increase.

Conclusion:

Thus, an example of billiard ball specifies this process.

(b)

To determine

A specific example that illustrates the given conditions.

Answer to Problem 82A

An example of a cricket ball.

Explanation of Solution

Given:

It is given that no work is done on the system, but potential energy is changed to kinetic energy.

When a cricket ball gets hit by the bat, the potential energy is changed into the kinetic energy of the ball. System consists of ball and Earth and thisindicates that there is no work done on the system. Hence, there is change in potential energy but no work is done on the system.

Conclusion:

Thus, an example of cricket ball specifies this process.

(c)

To determine

A specific example that illustrates the given conditions.

Answer to Problem 82A

An example of a pull-back toy car.

Explanation of Solution

Given:

It is given that when a work is done on the system, there will be an increase in potential energy while the kinetic energy remains unchanged.

Consider an example of pull-back toy car. Ifthe toy car is pulled back, it will move in the forward direction with the increasing speed. This is because,an internal coil spring is winded up by engaging the internal clockwork motor.So, the energy stored during pullback will be released which results in the forward motion of the toy car.

Conclusion:

Thus, an example of a pullback toy car specifies this process.

(d)

To determine

A specific example that illustrates the given conditions.

Answer to Problem 82A

An example of a speeding car on a road.

Explanation of Solution

Given:

It is given that work is done by the system. There is a decrease in kinetic energy while the potential energy remains unchanged.

Consider a car that initially speeds up on a road but after sometime, it reduces its speed by applying brakes. In this situation, the potential energy is unchanged. Since the car reduces its speed, so the kinetic energy will be decreased.Hence, work is done by the system.

Conclusion:

Thus, an example of a speeding car specifies this process.