Power and Work

Power is the RATE at which work is done. 

• True

• False

What is needed to calculate work?

• force

• distance

• time

• mass

Force multiplied by distance equals...

• work

• power

You use 950 J of energy to push a sofa. If it took you 5 sec to move the sofa, what was your power?

• 190 J

• 4750 J

• 4750 W

• 190 W

A runner exerts 240,000 J when she runs for 10 min. What is the runner's power?

• 400 W

• 600 W

• 400 J

• 600 J

Tags

NGSS.MS-PS3-4

The power rating of an electric lawnmower is 3000 W. If the lawnmower is used for 60 sec, how many joules of work can it do?

• 270,000 W

• 270,000 J

• 180,000 J

• 33.3 W

Tags

NGSS.HS-PS3-1

A 400 N object is in a 32,000 N elevator that rises 30 m in 2 min. How much power is needed for the elevator's trip?

• 8100 J

• 972,000 J

• 972,000 W

• 8100 W

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

NGSS.MS-PS2-1

NGSS.MS-PS2-2

A student who weighs 350 N climbs a flight of stairs 6 m high in 10 sec. How much power does the student need to do this?

• 35.6 J

• 35.6 W

• 210 W

• 583 J

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A force applied on a block accelerates across a horizontal, frictionless surface. The energy gained by the block is equal to which?

• the momentum given to the block

• the work done on the block

• the power applied to the block

• the impulse applied to the block

Tags

NGSS.MS-PS3-5

NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS3-1

Power is measured in which units?

• Newtons

• Joules

• Watts

• Joule/sec