6.8A Potential and Kinetic Energy

Suppose the skater is at the highest point in the jump. How do the relative amounts of the skater’s kinetic and gravitational potential energy compare at that point?

• all kinetic energy, no gravitational potential energy

• half kinetic energy, half gravitational potential energy

• no kinetic energy, all gravitational potential energy

• no kinetic energy, no gravitational potential energy

Answer explanation

At the highest point of the jump, the skater momentarily stops. So, the skater has a maximum amount of gravitational potential energy and no kinetic energy.

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6.8A

Which of the following statements about the kinetic and potential energy of the skater are true? Select all that apply.

• As the skater rolls up the side of the half-pipe, the skater gains kinetic energy.

• The skater has the minimal gravitational potential energy at the bottom of the half-pipe.

• Gravitational potential energy becomes kinetic energy when the skater rolls down the side of the half-pipe.

• The skater transfers gravitational potential energy to the skateboard.

Answer explanation

At the top of the half-pipe, the skater has maximum potential energy. As the skater rolls down, that potential energy is transformed into kinetic energy. At the bottom of the half-pipe, the skater has maximum kinetic energy and minimum potential energy.

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6.8A

Eating a healthy breakfast gives your body the energy needed to help you start your day. The girl in the photo is having cereal and orange juice, which have stored ​ (a)   , energy, a form of​ (b)   energy. The girl’s body breaks down the components of the food to access the energy stored in them. Later in the day, some of this energy is transformed into the​ ​ (c)   energy that will allow the girl to study and play sports. Some of the energy is also transformed into ​ ​ (d)   energy that keeps her body warm.

• chemical
• potential
• kinetic
• thermal
• mechanical
• nuclear
• solar

Answer explanation

Chemical energy, a form of potential energy, is stored in food. Some of this energy is transformed into kinetic energy that allows you to move, and some energy is transformed into thermal energy to keep you warm.

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6.8A

You are interested in improving the safety in the parking lot of your school and have made the following table. The table compares the kinetic energies of different vehicles likely to use the parking lot during school hours.

What pattern can you identify by analyzing the data in the table?

• As the speed of a moving object increases, the kinetic energy remains constant.

• As the speed of a moving object increases, the kinetic energy begins to decrease.

• As the speed of a moving object increases, the kinetic energy increases at the same rate.

• As the speed of a moving object increases, the kinetic energy increases at a higher rate.

Answer explanation

The same object has a much higher kinetic energy, even if the speed is only slightly higher.

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6.8A

A rock falls over a waterfall as shown in the diagram. At which point does the rock have the most potential energy?

• 2

• 3

• 4

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NGSS.MS-PS2-4

The drawing shows two identical airplanes at an air show. The airplanes are flying at the same speed. Airplane W is flying 50 m higher than Airplane X. Which statement best describes the energy of the two airplanes?

• Airplane W has a greater kinetic energy than Airplane X.

• The two airplanes have the same gravitational potential energy but different kinetic energies.

• Airplane X has more gravitational potential energy than Airplane W.

• The two airplanes have the same kinetic energy but different gravitational potential energies.

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NGSS.MS-PS3-2

Which statement explains the difference between potential and kinetic energy?

• Potential energy describes an object's acceleration, and kinetic energy describes an object's velocity

• Potential energy is energy stored within an object due to its relative position to the ground, and kinetic energy is the energy of motion

• Kinetic energy is energy stored within an object, and potential energy is the energy of motion

• Potential energy describes an object with a net force greater than zero, and kinetic energy describes an object with a net force of zero

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NGSS.MS-PS3-2

Which conclusion accurately describes the energy of the child sliding down the slide?

• Kinetic energy increases and potential energy decreases

• Kinetic energy decreases and potential energy increases

• Potential energy and kinetic energy decrease

• Potential energy and kinetic energy increase

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NGSS.MS-PS3-1

NGSS.MS-PS3-5

Students conducted an experiment by stretching the same rubber band to various lengths, releasing it, and measuring how far it traveled.

Based on the chart, what conclusion can be drawn?

• The more mass that a rubber band has, the more difficult it is to move.

• The shorter the length of a rubber band, the less energy can be stored in it.

• The more potential energy put into a rubber band, the more kinetic energy released.

• The farther a rubber band travels, the less it can be stretched later on.

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NGSS.MS-PS3-2

NGSS.MS-PS3-1

NGSS.MS-PS3-5

NGSS.MS-PS2-2

What type of energy is stored in a fully extended rubber band?

• Gravitational potential energy

• Kinetic energy

• Elastic potential energy

• Chemical energy