Forms of Energy

At the bottom of a steep hill, river water turns a wheel. The energy from the river water is transferred to a water wheel, which turns to generate electricity. How does the water's speed before turning the wheel compare to the speed after?

• The water's speed will be greater, pushed by the force of the wheel.

• The water's speed will be greater since the wheel's kinetic energy is going with it.

• The water's speed will be less since the force of the wheel has pushed against it.

• The water's speed will be less since the wheel's kinetic energy was going in the opposite direction of the water.

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NGSS.MS-PS3-5

A riverbed slopes steeply down a hill. Which statement BEST explains the water's potential energy at the top and bottom of the hill, all else being equal?

• The potential energy of the water at the top of the hill will be less than the potential energy at the bottom because the water at the top is higher in Earth's gravitational field.

• The potential energy of the water at the top of the hill will be greater than the potential energy at the bottom because the water at the top is higher in Earth's gravitational field.

• The potential energy of the water at the top of the hill will be less than the potential energy at the bottom because the water at the bottom is higher in Earth's gravitational field.

• The potential energy of the water at the bottom of the hill will be greater than the potential energy at the bottom because the water at the bottom is higher in Earth's gravitational field.

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NGSS.MS-PS2-2

Potential and kinetic energy are important to a roller coaster experience. Study the model of the roller coaster below. At which point in the track do the cars have the most kinetic energy?

• at the top of the loop

• at the bottom of the small hill

• at the bottom of the big hill

• on the downhill slope of the first hill

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A pot of water has started boiling. What type of energy transformation takes place when this happens?

• Kinetic energy is transformed to heat energy.

• Heat energy is transformed to kinetic energy.

• Potential energy is transformed to heat energy.

• Kinetic energy is transformed to potential energy.

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An auto company technician is trying to relate a car’s damage in a crash test to the kinetic energy of the car on impact. In addition to the mass of the car, what ratio will the technician need in order to determine to complete his study?

• the ratio of time to speed

• the ratio of weight to mass

• the ratio of distance to time

• the ratio of acceleration to speed

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NGSS.MS-PS3-1

NGSS.MS-PS3-5

Two cars have the same engine. One car has a mass of 1,000 kg, and the other has a mass of 2,000 kg. When both cars accelerate to 80 km/ht, the 2,000-kg car burns more gasoline than the 1,000-kg car does. Which claim can be made based on this data?

• The 1,000-kg car accelerates faster.

• The 2,000-kg car has more kinetic energy at 80 km/hr.

• The 2,000-kg car had more potential energy before both cars started.

• The 1,000-kg car and the 2,000-kg care were traveling in opposite directions.

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NGSS.MS-PS2-2

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Elizabeth is picking oranges with her family. An orange, high on a branch of an orange tree, falls to the ground. At which point does the orange have the MOST kinetic energy?

• just after it falls

• just before it falls

• just after it hits the ground

• just before it hits the ground

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NGSS.MS-PS3-1

NGSS.MS-PS3-5

A wrecking ball, is a type of pendulum used to demolish buildings. Engineers built a model of a wrecking ball to help them design a full-scale one that can destroy a building that must come down. The model has a 1-kg ball, and the full-scale machine they plan to use has a 1,000 kg ball. The kinetic energy needed to bring down the building can be estimated. The engineers make a graph of height versus kinetic energy for the model and calculate how this graph would change for the full-scale machine. Which question are the engineers trying to answer?

• What is the kinetic energy of the 1-kg ball?

• What is the potential energy of the building?

• Can the full-scale machine swing the ball high enough?

• How many times will they have to hit the building with the ball?

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NGSS.MS-PS3-1

Three students are about to dive from the high boards into the pool. The boys are on diving boards that are 3 m above the water, and a girl is on a board that is 5 m above the water. Using the picture as a model of energy levels, which of these has the MOST gravitational potential energy?

• the girl

• the tallest boy

• the heaviest boy

• the boys combined

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NGSS.MS-PS3-2

Four skydivers jumped out of the same plane at the same time. Two have opened their parachutes, and two have not. Use the picture as a model of relative potential energy. Which skydiver has the most gravitational potential energy.

• Skydiver A

• Skydiver B

• Skydiver C

• Skydiver D

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