Class 9 Science: work and energy (conservation of energy)
Release a ball in a U-shaped ramp and watch potential energy turn into kinetic energy and back.
Words to know
Potential energy
Stored energy because of height: mgh.
Kinetic energy
Energy of motion: ½mv².
Conservation of energy
Energy changes form but the total stays the same.
Friction
A force that turns some energy into heat.
Quick check
Answer 3 questions to check what you learned.
Try at home
Swing on a swing (or watch a pendulum). Where are you fastest? Where do you stop for a moment? Those are the points of most kinetic and most potential energy.