The Basics
What is energy?
The ability to do work.
What is kinetic energy?
The energy an object has because it is moving.
What happens to the potential energy of an object when it is raised higher?
Its potential energy increases.
How are speed and kinetic energy related?
If speed increases, kinetic energy increases. If speed decreases, kinetic energy decreases.
What happens to stored energy in a trampoline when you jump on it?
It is converted to energy of motion, pushing you back up.
What are the two main forms of energy scientists classify?
Stored energy (potential energy) and energy of motion (kinetic energy).
What happens to your kinetic energy when you slow down on a bicycle?
Your kinetic energy decreases.
What type of potential energy does a stretched trampoline have?
Elastic potential energy (stored energy due to being stretched).
How long does it take a top fuel dragster to complete a 0.4 km (¼ mile) race?
About 4 seconds.
When you stop moving, what happens to your kinetic energy?
You no longer have energy of motion — kinetic energy drops to zero.
What is potential energy?
Energy that is stored inside an object that is not being used now but can be used later.
Besides speed, what else does kinetic energy depend on?
Mass — an object with greater mass has more energy of motion.
Why does an object above a surface have potential energy?
Because of its position — being above the surface gives it stored gravitational energy that can be used later.
In the Moving Ball experiment, what was being tested?
How the height of a ramp affects the speed of a table tennis ball.
When a ball rolls down a ramp, what type of energy is it converting to kinetic energy?
Potential energy (stored energy due to its height/position).
Give two examples of objects that store potential energy.
An object above a surface, and a stretched trampoline (or spring).
If two objects travel at the same speed but have different masses, which has more kinetic energy?
The object with the greater mass.
On a roller coaster, where would the car have the most potential energy?
At the highest point on the track.
In the Moving Ball experiment, which ramp height would make the ball travel fastest — one book, two books, or three books?
Three books — the greater the height, the faster the ball travels.
How does gravity act as a force to change energy in a thrown baseball?
Gravity acts on the ball causing it to move downward, affecting its speed and direction.
An airplane is flying above the ground. What two types of energy does it have, and why?
Potential energy because it is above the ground, and kinetic energy because it is moving.
Describe how a pitcher, gravity, and a catcher each change the kinetic energy of a baseball.
The pitcher applies force to start the ball moving (gives it kinetic energy). Gravity acts on it moving it downward. The catcher applies force to decrease its speed, so kinetic energy decreases.
On a roller coaster, what happens to potential energy and kinetic energy as the car goes down a hill?
Potential energy decreases as the car loses height, and kinetic energy increases as the car speeds up.
A pitcher throws a baseball. How does applying force give the ball energy, and what type of energy is it?
The pitcher applies force to the ball, causing it to start moving. This gives it kinetic energy — energy of motion.
Explain the full energy transformation of a roller coaster from the top of the first hill to the bottom.
At the top, the car has maximum potential energy and low kinetic energy. As it descends, potential energy converts to kinetic energy — the car speeds up. At the bottom, kinetic energy is at its highest and potential energy is at its lowest.