AP Physics Work and Energy

An 8-kg object is raised by a crane to the top of a building 20-meters in height. If it takes 50 seconds for the object to get to the top of the building, then how much power was needed?

• 1600 watts

• 3.2 watts

• 32 watts

• 200 watts

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NGSS.HS-PS2-1

NGSS.HS-PS2-4

A rocket of mass m begins to ascend vertically at v m/s. The work that gravity does on the rocket is:

• Negative

• Zero

• Positive

• Undefined

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NGSS.HS-PS2-4

A kg-m²/s² is otherwise known as a(n)

• Newton

• Joule

• Watt

• Displacement

How are work and energy related? 

• The work done by an external force acting on an object causes a change in the mechanical energy of the object.

• Work is the same thing as energy.  They are equal. 

• Energy is m*g*h, and work is 1/2*m*v²

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NGSS.HS-PS2-1

If you pull the trolley along a flat floor horizontally. Which force do you use to calculate the work done.

• Weight

• Pulling force

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NGSS.HS-PS2-1

If the net work done on an object is negative, then the object’s kinetic energy:

• decreases

• remains the same

• increases

• is zero

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NGSS.HS-PS3-1

NGSS.HS-PS3-2

Use the law of conservation of energy (assume no friction) to find "E" for a 500-kg roller coaster following this path.

• 51.0 m/s

• 40.8 m/s

• 28.3 m/s

• 31.6 m/s

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NGSS.HS-PS3-1

A crane lifts a steel beam weighing 8,000N, 300m in the air, then drops it onto a 20m high building below (for science!). The steel beam breaks through the ceiling. Assume that air resistance is negligible. Select the statement that best describes the scenario above.

• The beam has less energy when landing on the ground than it started with due to losing some to its surroundings

• The beam has the same amount of energy as it began with

• The kinetic energy as the beam touches the ground is equal to the potential energy it began with.

• The beam has a velocity of 19.8 m/s as it reaches the ground

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NGSS.HS-PS3-1

Rank the scenarios from least to greatest kinetic energy right before they hit the ground

• 2<3<1<4

• 2<1<3=4

• 2<1<3<4

• 1=2=3=4

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NGSS.HS-PS2-1

NGSS.HS-PS2-2

In which of the following situations do your arms do work on books?

• holding a heavy stack of books while standing

• carrying a heavy stack of books

• dropping a stack of books onto a table

• picking up a pile of books from the floor