Skill 5 of 9
In Progress

Elastic & inelastic collisions

Jumping on a trampoline’ and ‘jumping on asphalt’ are of course two very different feelings. The “impact” with the surface is very different. In one case, you are thrown back up, in the other you are not.

As if the trampoline “conserves” your speed and “gives it back” to you upwards, whereas the asphalt just “absorbs” it.

  • Why don’t we name impacts – or collisions – where the ‘speed is “stored” or “conserved”elastic collisions,1 2 and
  • impacts or collisions where the ‘speed is “absorbed”inelastic collisions.

There are many elastic collisions around us, like

  • billiard balls colliding,3
  • a tennis ball bouncing off a wall,4
  • trampoline jumping etc.,

where we see bouncing and the full speed “reappearing” after the impact. Also, there are many inelastic collisions around us, like

  • two cars crashing,5
  • a ball thrown into a pillow,
  • a bullet hitting and getting stuck in a wooden wall,
  • a tennis ball hitting a sticky wall (like with wet paint) etc.,

where the speed is “absorbed” and everything tends to stops moving.