Question 1

A 15.0 kg suitcase is lifted 3.0 m above a platform by a conveyor belt at a constant speed. How much work is done on the suitcase by the conveyor belt? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$147\ \mathrm{J}$$

Question 2

Which of the following best describes the work done by a force $$F$$ acting at an angle $$	heta to $$the direction of displacement $$d$$?

Accepted Answer

$$W = Fd\cos	heta$$

Question 3

A vacuum cleaner is pulled 3.0 m by a force of 50.0 N at an angle of $$30.0^\circ$$ above the horizontal. How much work is done by the force?

Accepted Answer

$$130\ \mathrm{J}$$

Question 4

Which of the following is the correct formula for kinetic energy?

Accepted Answer

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

Question 5

A 7.00 kg bowling ball moves at $$3.00\ \mathrm{m/s}. $$What is its kinetic energy?

Accepted Answer

$$31.5\ \mathrm{J}$$

Question 6

A 2.45 g ping pong ball must have the same kinetic energy as a 7.00 kg bowling ball moving at $$3.00\ \mathrm{m/s}. $$What speed must the ping pong ball have? (1 g = $$0.001 kg)$$

Accepted Answer

$$160.5\ \mathrm{m/s}$$

Question 7

Which statement best describes the Work-Energy Theorem?

Accepted Answer

The net work done on an object is equal to its change in kinetic energy.

Question 8

A 10.0 kg sled is kicked on a frozen pond, giving it an initial speed of $$2.2\ \mathrm{m/s}. If $$the coefficient of friction between the sled and the ice is $$0.10$$, how far will the sled travel before coming to rest? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.46\ \mathrm{m}$$

Question 9

Which of the following is the correct formula for gravitational potential energy?

Accepted Answer

$$PE = mgh$$

Question 10

A ball of mass 2.0 kg is resting on a hill that is 5.0 m high. What is its gravitational potential energy relative to the base of the hill? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$98\ \mathrm{J}$$

Question 11

A stuntman is attached to a bungee cord with a spring constant of $$71.8\ \mathrm{N/m}. $$When he finally stops, the cord has stretched by $$44.0\ \mathrm{m} - 15.0\ \mathrm{m} = 29.0\ \mathrm{m}. $$What is the elastic potential energy stored in the cord?

Accepted Answer

$$30,200\ \mathrm{J}$$

Question 12

Which of the following best describes the Law of Conservation of Energy?

Accepted Answer

Energy is never created or destroyed, only transformed from one form to another.

Question 13

A child of mass 25.0 kg starts from rest and slides down a frictionless slide from a height of 2.0 m. What is her speed at the bottom of the slide? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$6.26\ \mathrm{m/s}$$

Question 14

Which of the following is the correct formula for elastic potential energy stored in a spring?

Accepted Answer

$$PE = \frac{1}{2}kx^2$

Question 15

A curtain of mass 20.0 kg needs to be raised 7.5 m at constant speed in 5.0 s. What is the minimum power required to do this? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$294\ \mathrm{W}$$

Question 16

Which of the following is the correct definition of power in physics?

Accepted Answer

The rate at which work is done or energy is transferred.

Question 17

A motor is rated at 1.0 kW. How much work can it do in 10 seconds?

Accepted Answer

$$10,000\ \mathrm{J}$$

Question 18

Which of the following is NOT a form of mechanical energy?

Accepted Answer

Thermal energy

Question 19

A 5.0 kg object is moving at $$4.0\ \mathrm{m/s}. If $$its speed is doubled, by what factor does its kinetic energy increase?

Accepted Answer

4

Work, Energy, and Power: Fundamental Concepts in Physics

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