Energy, Work, Power and Efficiency

Work is measured in which units?

• Newtons

• Joules

• Watts

• Joule/sec

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Power is measured in which units?

• Newtons

• Joules

• Watts

• Joule/sec

Tags

NGSS.MS-PS3-5

____ is being done when a force is exerted on a wagon while it is being pulled up a hill.

• Power

• Force

• Work

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

Tags

NGSS.MS-PS2-1

NGSS.MS-PS3-1

NGSS.MS-PS3-5

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

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.MS-PS3-4

NGSS.MS-PS3-5

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

• 30 watts
• 3 watts
• 120 watts
• 270 watts

Work divided by time equals...

• energy
• power

The amount of work done in a certain amount of time is known as 

• work
• effort force
• resistance force 
• power

A cake mixer is capable of doing 500 J of work over the course of 2.5 seconds. What is the power output of the cake mixer?

Tags

NGSS.MS-PS3-5