2.4 Work & Power

Multiple Choice

Energy is

• how fast you do something.

• the ability to do work.

• confusing.

• how fast you lift something.

Multiple Choice

If you use 30 J of energy to move an object, you have done ____ J of work.

• 3

• 10

• 30

• 0

Multiple Choice

Jane carries a 5 kg box and Lorie carries a 10 kg box up a set of stairs, who did more work?

• Jane because his box was lighter.

• Lorie because her box weighed more.

• Can't tell.

Multiple Choice

If you lift a box that is twice as heavy as your friend you are doing

• the same amount of work.

• two times more work than your friend.

• half as much work as your friend.

• Cannot be determined.

Multiple Choice

You push a crate with a force of 100 N for 5 meters. How much work did you do?

• 500 J

• 100 J

• 50 J

• 5 J

Multiple Choice

How much power is generated by Ashley (50 kg) running up a 6 m flight of stairs in 5 seconds?

• 60 W

• 62 W

• 600 W

• 1500 W

Multiple Choice

Work is done only if

• a force is applied.

• the force applied causes the object's motion.

• an object is in motion.

Multiple Choice

If you carry a 5 kg box across the room at a constant velocity

• you do no work.

• you do some work.

• you do negative work.

• Cannot be determined.

Multiple Choice

On a work vs time graph, you can calculate the power by

• the area.

• the y-axis.

• the y-intercept.

• the slope.

Multiple Choice

How much power was generated from 0-4 seconds?

• 1100 W

• 4 W

• 267 W

• 1600 W

Multiple Choice

How much work is done?

• 9 J

• 18 J

• 27 J

• 36 J

Multiple Choice

If it took 9 seconds for the object to move 6 meters, what's the power?

• 81 W

• 27 W

• 3 W

• 6 W

Multiple Choice

If you run up the stairs slower you will

• do more work.

• do less work.

• generate more power.

• generate less power.

Multiple Choice

What is the kinetic energy of a 10 kg ball moving at 3 m/s?

• 15 J

• 30 J

• 45 J

• 90 J

Multiple Choice

A 5 kg cat falls off a 3 m tall fridge. What is the cat's PE as it starts to fall?

• 15 J

• 30 J

• 150 J

• 1470 J

Multiple Choice

A 5 kg cat falls off a 3 m tall fridge. What is the cat's KE just before it lands on the floor?

• 15 J

• 30 J

• 150 J

• 1470 J

Multiple Choice

What is the mass of an object with 1200 J of PE when it is 5 meters above the ground?

• 10 kg

• 24 kg

• 100 kg

• 240 kg

Multiple Choice

What kind of energy(ies) does the car have at position A? The ground is h=0.

• KE

• KE + PE

• PE

• KE - PE