Question 1

If you lift a box with twice the force but only move it half the distance, how does the work done compare to lifting it with the original force over the full distance?

Accepted Answer

The work done is the same as before.

Question 2

When you double the force applied to an object but halve the distance over which it is applied, what happens to the total work done?

Accepted Answer

The total work done remains unchanged.

Question 3

If you do the same amount of work in half the time, what happens to the power output?

Accepted Answer

The power output is doubled.

Question 4

A person and their grandchild, both of the same mass, walk up the same flight of stairs. The grandchild runs up in half the time. Who generates more power?

Accepted Answer

The grandchild, because power depends on how quickly the work is done.

Question 5

If you increase your speed from 2 m/s to 4 m/s, by what factor does your kinetic energy increase?

Accepted Answer

By a factor of four.

Question 6

Which of the following statements about kinetic energy is correct?

Accepted Answer

Kinetic energy is always positive.

Question 7

A motorcycle travels at a constant speed in a straight line. What is the net work done on the motorcycle?

Accepted Answer

Zero, because there is no change in kinetic energy.

Question 8

Which of the following is true about the work done by a force when the displacement is perpendicular to the force?

Accepted Answer

No work is done.

Question 9

If an object moves in a circle at constant speed, what can be said about the net work done by the centripetal force over one complete revolution?

Accepted Answer

The net work done is zero.

Question 10

Which of the following best describes the work-energy theorem?

Accepted Answer

The net work done on an object equals its change in kinetic energy: $$ \Delta KE = W_{net} $$

Question 11

Energy cannot be ______.

Accepted Answer

Destroyed

Question 12

A car's speed increases from 10 m/s to 20 m/s. By what factor does its kinetic energy increase?

Accepted Answer

By a factor of four.

Question 13

A 1 kg object slows down from 4 m/s to rest on a level surface. What is the net work done on the object?

Accepted Answer

$$ -8 \ 	ext{J} $$

Question 14

In a simple machine, how much work is done when an input of 10 N acts over a distance of 5 m?

Accepted Answer

$$ 50 \ 	ext{J} $$

Question 15

Which of the following is a correct statement about the sign of work done by a force?

Accepted Answer

Work is positive if the force and displacement are in the same direction.

Question 16

A force of 5 N acts on an object and moves it 3 m in the direction of the force. How much work is done?

Accepted Answer

$$ 15 \ 	ext{J} $$

Question 17

If a force acts at an angle $$ 	heta  to $$the direction of displacement, the work done is given by:

Accepted Answer

$$ W = Fd \cos 	heta $$

Question 18

Which of the following is true about the kinetic energy of an object?

Accepted Answer

$$ KE = \frac{1}{2}mv^2$ $$

Question 19

A box is pushed across a rough floor at constant speed. What can be said about the net work done on the box?

Accepted Answer

The net work done is zero.

Question 20

If the net work done on an object is zero, what happens to its kinetic energy?

Accepted Answer

There is no change in the object's kinetic energy.

Study Notes on Work, Energy, and Kinetic Energy

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드