Compare the amount of flexing of the 2 metal hoops when the carts collide. What does this tell you about the size of the forces acting on the carts during the collision?
(For frame-by-frame viewing, click the “.mp4” link. When the video plays in your browser using Quicktime, pause the video before the collision and use the left-right arrow keys to advance the video one frame at a time. Compare the sizes of the hoops!)
FAST vs. SLOW (same mass)
HEAVY vs. LIGHT (same speed)
HEAVY (moving) vs. LIGHT (at rest)
HEAVY (at rest) vs. LIGHT (moving)
Action-Reaction 