Unit 9.Quiz 3.LT 3/4

[LT 3] You drop a 5 kg ball from a height of 2 m. Just before it reaches the ground, what is the ball's velocity?

• 6.26 m/s

• 40 m/s

• 4.47 m/s

• 100 m/s

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U9.LT 3

[LT 3] At some point during a fall, an object has 183 J of KE and 117 J of PE. What is the mechanical energy of the system? Please answer with the number and the unit.

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U9.LT 3

[LT 3] At which point(s) on the roller coaster is the kinetic energy at its maximum?

• A

• B

• C

• D

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U9.LT 3

[LT 4] What's the efficiency of a microwave that does 850 J worth of work when it uses 3400 J of electricity to run?

• 5.86%

• 2550%

• 25%

• 0.25%

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U9.LT 4

[LT 4] How much time is needed to produce 720 Joules of work if 90 watts of power is used?

• 64,800 s

• 0.125 s

• 8 s

• 80 s

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U9.LT 4

[LT 4] You do 90 Joules of work in 30 seconds. How much power have you generated?

• 30 Watts

• 3 Watts

• 120 Watts

• 270 Watts

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U9.LT 4

[LT 4] If 68 Joules were necessary to move a 4 Newton crate, how far was the crate moved?

• 272 m

• 17 m

• 4.05 m

• 272 cm 

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U9.LT 4

[LT 4] How much power is the tractor that drags a plow with a force of 500 N a distance of 10 meters in 20 seconds?

• 250 Watts

• 250 Joules

• 100,000 Watts

• 100,000 Joules

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U9.LT 4

[LT 4] Match these units

• Work

• Watts

• Distance

• Joules

• Power

• meters

• Force

• Newtons

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U9.LT 4