Adding a bungee cord
This time you will try a "reverse" collision. You will measure the force on a bungee cord attached to the air cart when it stretches and bounces back. Connect the Force probe to your handheld computer. Refer to Technical Hints to see how to connect the cables.
Place the Force probe on its side wedged in a pile of books so that it is at the same height as the bumper of your cart. It could also be clamped to a ring stand. Have someone hold the Force probe down firmly during the experiment. Unscrew and set aside the larger eyebolt if it's in the way.
Cut a long rubber band to make a bungee cord. Attach one end to the Force probe and the other end to the cart. Use several rubber bands if needed so that the cord is about 1/2m long.
Line up the cart with the Force probe, with the rubber band lying loosely between them. Hook things together with paper clips.
Start the software. Start recording the force. Give the cart a push so that it stretches the bungee cord and then bounces back. Catch it before it hits the Force probe. Stop recording. Observe the behavior of the acrobat.
Try this several times, and after a good bounce save your data to the handheld computer.
Examine the graph. Zoom in on your collision until it fills most of your screen.
Answer the following in Notes on your handheld computer:
What is the shape of the plot?
How long did the collision take?
What was the maximum force?
What did the acrobat do during the collision?
