Understanding Mechanical Energy

David jumps on a trampoline. When he reaches the highest point, what type of energy is the greatest?

• A. Kinetic energy

• B. Potential energy

• C. Heat energy

• D. Electrical energy

A soccer ball is rolling on the grass. What type of energy does it have?

• A. Only potential energy

• B. Only kinetic energy

• C. No energy

• D. Both kinetic and potential energy

An apple is hanging from a tree. What happens to the energy when it falls?

• A. Kinetic energy turns into potential energy

• B. Potential energy turns into kinetic energy

• C. The energy disappears

• D. The apple has no energy

A car moves up a hill, stops for a moment at the top, and then moves down.

What happens to the energy as the car moves down?

• A. Potential energy changes into kinetic energy.

• B. Kinetic energy changes into potential energy.

• C. Mechanical energy disappears.

• D. Only kinetic energy exists.hemical energy

In Step 2, the person lifts the hammer before swinging it down. What type of energy is most important at this moment?

• A. Only kinetic energy, because the hammer is moving fast.

• B. Only potential energy, because the hammer is high and not moving yet.l energy

• C. Both kinetic and potential energy, because the hammer is high and already moving.

• D. No energy, because the person is holding the hammer.

In Step 3, when the hammer hits the nail, its kinetic energy is at its maximum. What is the best explanation for this?

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• A. The hammer is at its highest position, so it has more stored energy.

• B. The hammer is moving at its fastest speed just before impact.

• C. The hammer stops moving, so kinetic energy increases.

• D. The hammer loses all its energy when it touches the nail.

Which type of energy shown in the picture includes potential energy?

• A. Light energy, because it travels in waves.

• B. Gravitational energy, because it depends on height and position.

• C. Radiant energy, because it comes from the Sun.

• D. Electrical energy, because it moves through circuits.

A box moves along the track shown in the image. At which point does the box have the highest kinetic energy and the lowest potential energy?

• A. Point 1, because it is at the top of the first hill.

• B. Point 3, because it is at the lowest position and moving fastest.

• C. Point 4, because it is moving down from the second hill.

• D. Point 5, because it has the greatest height.

Mechanical energy is the sum of kinetic energy (energy of motion) and potential energy (energy stored due to position). In an ideal system without friction, mechanical energy remains constant.

In the image, at which point does the box have the greatest mechanical energy?

• A. Point 1, because it is at a high position.

• B. Point 3, because it has the greatest kinetic energy.

• C. Point 5, because it has the maximum height.

• D. Mechanical energy is the same at all points.

When you lift one ball and let it go, what happens to the last ball?

• A. All the balls move at the same time.

• B. No ball moves because the energy disappears.

• C. Only the last ball moves because the energy passes through the middle balls.

• D. The first ball stops, and nothing else moves.