Trampoline Bounce

This simulation models the mat as a spring with damping. The jumper stores energy in the stretched mat and gets it back as speed, but real mats lose some energy, so each peak is lower by the factor e squared, where e is the restitution. Students drag the jumper to set a drop height and read drop height, last peak, first peak ratio, mat depth and force over weight. Sliders set restitution, mat stiffness, mass and gravity, so students can bounce on the Moon. Teachers can use it for springs and energy loss.

• Drag the jumper up and release, then compare the Drop height and Last peak readouts.
• Lower Restitution e to 0.5 and see how quickly the bounces die away.
• Raise Mat stiffness and check how the Mat depth readout changes.
• Set Gravity to 1.6 and bounce again to see a Moon-like hop.
• Push the jumper down into the mat and release to start with the mat already compressed.

1. 1Describe the mat as a spring that stores and returns energy.
2. 2Predict how the next peak compares with the last using restitution.
3. 3Explain how gravity and stiffness change the bounce.
4. 4Interpret mat force relative to body weight.

Questions teachers ask