Work, Power and Energy

Work is measured in which units?

• Newtons

• Joules

• Watts

• Joule/sec

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NGSS.MS-PS3-4

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Power is measured in which units?

• Newtons

• Joules

• Watts

• Joule/sec

A strongman exerts 1500 N on the side of a building. After 2 minutes, the building doesn't move. How much work did he do?

• 180,000 J

• 0 J

• 750 J

• 1500 J

An Xbox consumes 15.7 watts while in standby mode. If you leave it in standby mode for 86,400 seconds (one day), how much work was done?

• 1,356,490 J

• 1,356,480 J

• 1,356,470 J

• 1,356,460 J

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NGSS.MS-PS3-5

You move a 0.8 kg object five meters in 4 seconds. How much power have you generated?

• 160 watts

• 10 watts

• 6.4 watts

• 17 watts

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NGSS.MS-PS3-5

If two rocks are launched through the air at the same speed, but one has twice as much mass as the other, how do their kinetic energies compare?

• The kinetic energy of the two rocks is the same because they have the same speed

• The rock with the greater mass will only move a small distance and then fall straight to the ground

• The two rock could not have the same speed if they have different masses

• The rock with the greater mass has more kinetic energy than the rock with less mass even though they are traveling at the same speeds because both mass and speed affect kinetic energy.

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Which point has the most kinetic energy?

• Ball G

• Ball F

• Ball E

• Ball D

• Ball A

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NGSS.MS-PS3-1

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As a pendulum swings from its highest to lowest position, what happens to its kinetic and potential energy?

• Both the potential energy and kinetic energy decrease

• The potential energy decreases while the kinetic energy increases

• The kinetic energy decreases while the potential energy increases

• Both the potential energy and kinetic energy increase

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NGSS.MS-PS3-2

NGSS.MS-PS3-5

An object has 12.4 J of potential energy and 23.5 J of kinetic energy. What is the mechanical energy of the system?

• 11.1 J

• 1.895 J

• 35.9 J

• 291.4 J

An Olympic high jumper, with a mass of 82 kg, has a maximum gravitational potential energy of 1970 J. How high was the jump?

Let g = 9.8N/kg

• 24 m

• 161,540 m

• 2.5 m

• 201 m

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