Energy, Work, Power and Efficiency

Work is a measure of the energy needed to apply a force across a _______.

• time
• distance
• gravity
• object

Efficiency is a ______ of what you put in versus what you get out of a system.

• source
• ratio
• multiplication
• addition

An object has a weight of 200 N and is moved 3 meters.  How much work is done?

• 66.7 J
• 600 J
• 203 J
• 0.015 J

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

You are pushing a car as hard as you can for 5 minutes, but cannot get it to move.  How much work have you done on the car?

• There is not enough information to calculate the work.
• If you used 20 newtons of force, you will have done 100 Joules of work
• None. There was no movement.
• None of the answers are correct.

Find the work of a turtle that has a force of 27 newtons and travels a distance of 3 meters.

• 81 watts
• 81 joules
• 9 watts
• 9 joules

What units are used to measure work?

• Meter
• Watts
• Newtons
• Joules

What units are used to measure force?

• Joules
• Newtons
• Newton-meter
• Watt

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

What units are used to measure energy?

• Watts
• Newtons
• Joules
• kilowatts

What is the useful work output of a machine that consumes 2,800 Joules and an efficiency of 40%?

• 7000 J

• 2760 J

• 1120 J

Tags

NGSS.HS-PS3-3

Calculate the efficiency of a machine when 55.3 J of work input produces 14.3 J output?

• 41 J

• 26%

• 386%