Power

You do 90 joules of work in 30 seconds. How much power have you generated?

• 30 watts

• 3 watts

• 120 watts

• 270 watts

If 68 W of power is produced in 18 seconds, how much work is done?

• 1,224 J

• 0.264 J

• 3.77 J

• 12.24 J

How much time is needed to produce 720 Joules of work if 90 watts of power is used? 

• 0.125 s

• 8 s

• 64800 s

• 80 s

A 100 N force is applied to move an object a horizontal distance of 5 meters at constant speed in 10 seconds. How much power is done?

• 50J

• 50W

• 500J

• 500W

What is the difference between calculating power and work?

• Power takes into account the time it takes to complete a task
• Work takes into account the time it takes to complete a task
• Power is force/area
• Work is force/area

Bobby lifts a book to the second floor in 20 seconds. Carol lifts the same book to the second floor in 10 seconds. Who did more work?

• Bobby

• Carol

• They did the same amount of work

• Not enough information

A girl weighs 400 N. She runs up a flight of stairs of height 5 m in 4 seconds. Her power is:

• 320 W

• 400 W

• 500 W

• 2 000 W

Groot rescues Rocket from the bottom of a deep pit. Groot expends 1000 J of energy lifting Rocket who has a mass of 50 kg out of the pit. How deep is the pit?

• 0.5 m
• 2 m
• 4 m
• 10 m

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.

If you run up the stairs slower you will

• do more work.

• do less work.

• generate more power.

• generate less power.