Energy Transfer, Transformation & Conservation

Which of the following statements about energy is true?

i. Kinetic energy cannot be transformed into another type of energy.

ii. Kinetic energy can be transformed into potential energy.

iii. Potential energy can be transformed into kinetic energy.

iv. Potential energy cannot be transformed into another type of energy.

• i and iii only

• i and iv only

• ii and iv only

• ii and iii only

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NGSS.MS-PS3-4

NGSS.MS-PS3-5

In an electric toaster, electricity passes through thin metal wires (called filaments) inside the toaster, causing the wires to glow and heat up. The heat given off by the filaments then toasts the bread. If 500 kilojoules of electricity are supplied to a toaster, which choice below could represent the total amount of heat energy given off by the filaments of the toaster?

• 480 kilojoules

• 505 kilojoules

• 520 kilojoules

• 630 kilojoules

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NGSS.MS-PS3-4

NGSS.MS-PS3-5

It takes 86 joules of energy to raise a box 2 meters using the pulley setup shown above. Without the pulley, the box can be raised 2 meters using only 82 joules of energy. What could explain this 4-joule difference?

• When raising the box using the pulley, 4 joules of mechanical energy are destroyed.

• When raising the box using the pulley, 4 joules of mechanical energy are broken down into protons, neutrons, and electrons.

• When energy changes from one form to another, some energy is always changed to sound.

• When raising the box using the pulley, 4 joules of mechanical energy are converted into heat energy due to friction.

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NGSS.MS-PS3-4

When energy changes from one form to another, some energy is always changed to

• sound.

• heat.

• light.

• electricity.

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NGSS.MS-PS3-3

NGSS.MS-PS3-5

Lance is rubbing two sticks together. The friction causes the kinetic energy from rubbing the two sticks to be converted into

• electrical energy.

• potential energy.

• heat energy.

• chemical energy.

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

The law of conservation of energy states that

• energy cannot be created and it cannot change form.

• energy can be created and can be destroyed.

• energy cannot change form and it cannot be destroyed.

• energy cannot be created and it cannot be destroyed.

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NGSS.MS-PS3-2

NGSS.MS-PS3-3

NGSS.MS-PS3-5

In billiards, collisions occur between pool balls as they make contact with one another. In one particular collision, when all balls are initially at rest, a white ball is struck with a stick and makes contact with a red ball. The table below summarizes the motion of the white ball, with t = 0 when the white ball is initially struck by the pool stick. Assuming that the balls are on a surface with no friction, which table could summarize the motion of the red ball over the same time period?

• 
• 
• 
• 

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NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS3-1

Spinning wind turbine blades have kinetic energy. Wind turbines transform this energy into electric energy and heat energy in a closed system. Which of the following statements about this energy transformation is true?

• Half of the kinetic energy is transformed into electric energy and heat energy.

• All of the heat energy is transformed into electric energy.

• All of the kinetic energy is transformed into electric energy and heat energy.

• Half of the heat energy is transformed into electric energy.

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NGSS.MS-PS3-1

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Jed is skating down a ramp. As his height decreases, his _____ energy decreases, and his _____ energy increases.

• kinetic, potential

• potential, kinetic

• thermal, kinetic

• chemical, potential

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NGSS.MS-PS3-1

NGSS.MS-PS3-5

In a closed system, the total energy before an energy transformation is _____ the total energy after it.

• equal to

• greater than

• unrelated to

• less than

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NGSS.MS-PS3-4

NGSS.MS-PS3-5