Energy

What energy transformations occur when a noisy ceiling fan is turned on in a room?

• Chemical → Light → Mechanical

• Electrical → Mechanical → Sound

• Mechanical → Sound → Chemical

• Thermal → Electrical → Light

What energy transformations occur when propane gas is used to lift the balloon?

• thermal energy → chemical energy → light energy

• mechanical energy → light energy → chemical energy

• chemical energy → mechanical energy → thermal energy

• chemical energy → thermal energy → mechanical energy

The image below shows a tea kettle on a gas stove. Which statement describes the energy transformation that occurs when the tea kettle begins whistle as the water is heated on a stove that uses natural gas?

• The thermal energy in natural gas is transformed into sound energy when the water becomes hot. Then the sound energy changes into light energy when the kettle becomes warm.

• The chemical energy in natural gas is transformed into thermal energy which heats the water. The thermal energy transforms to sound and mechanical energy as the steam leaves the kettle.

• The light energy in natural gas is transformed into chemical energy in the water. Then the chemical energy changes into kinetic energy when steam leaves the kettle and into sound energy when the water boils.

• The electrical energy in natural gas is transformed into thermal energy which causes the water to form steam. Then the thermal energy changes into sound energy and light energy when the steam leaves the kettle.

Students conducted an investigation using basketballs. They dropped a basketball from a height of 100 centimeters (cm) and it bounced back to a height of 60 centimeters (cm). According to the Law of Conservation of Energy, which of the following statements best describes why the basketball did not bounce back to the original height?

• energy was created as the basketball bounced

• energy was destroyed as the basketball bounced

• energy transferred to the ground when it made contact with the basketball

• energy transferred to the basketball when it made contact with the ground

Which scenario best demonstrates the Law of Conservation of Energy?

• All the energy used to throw a ball is destroyed when it lands.

• When a fish uses all of its energy, it creates more by swimming less.

• Light energy is collected by solar panels and transformed into electrical energy.

• As a toy car starts to slow down until all of its energy is transferred into the ground.

The diagram below shows how energy transfers when headphones are plugged into a laptop to watch a video.

• Sound → Electrical → Light

• Mechanical → Electrical → Sound

• Light and Sound → Chemical → Electrical

• Chemical → Electrical → Light and Sound

The image below shows a swinging pendulum, Position 1 represents its starting point.

• The total amount of energy changes from Position 4 to Position 5.

• The total amount of energy increases from Position 1 to Position 2.

• The total amount of energy decreases from Position 3 to Position 5.

• The total amount of energy does not change from Position 2 to Position 4.