Gravity, Energy & Tides

Which of the following is an example of a change in energy due to an event?

• A battery in a flashlight turning chemical energy into light and heat.

• A balloon floating in the air.

• A rock lying on the ground.

• Water in a pot being left to cool down.

When a car accelerates, it changes chemical energy into ___ energy.

True or False

When a ball is thrown into the air, its kinetic energy is converted into potential energy as it rises.

When energy dissipates, it usually:

• Becomes more useful.

• Is completely lost.

• Becomes less useful and changes to heat.

• Is stored for later use.

In most processes, energy eventually changes into ___ energy, which is harder to use for doing work.

True or False

In a running fan, sound and heat energy is lost, making it less useful.

Which of the following is an example of energy dissipating in a system?

• A glowing light bulb.

• A car moving down a smooth road.

• A bike’s tires getting hot after braking.

• A charged phone battery.

Why is it said that energy tends to dissipate and become less useful?

• Energy tends to dissipate into heat or other forms that are harder to convert into useful work, which decreases its ability to be used efficiently.

• Energy is conserved in every form hence its less efficient.

• Heat and light energy only tend to dissipate and become useful.

Which of the following is true about gravity?

• Gravity is a force of attraction between objects that only affects objects on Earth.

• Gravity pulls objects towards the ground.

• Gravity only acts on the moon and not the Earth.

• Gravity is a force of attraction between any two objects with mass.

The strength of the gravitational force between two objects depends on their ___ and the distance between them.