A 50 g air-track glider is repelled by a post fixed at one end of the track. It is hypothesized that the glider’s potential energy is U = c/x, where x is the distance from the post and c is an unknown constant. To test this hypothesis, you launch the glider with the same speed at various distances from the post and then use a motion detector to measure its speed when it is 1.0 m from the post. Your data are as follows:

Initial distance (cm)...................Speed at 1.0 m (m/s)

2.0.........................................................1.40

4.0.........................................................0.98

6.0.........................................................0.79

8.0.........................................................0.68

a. Do the data support the hypothesis? To find out, you’ll need to compare the shape of an appropriate graph to a theoretical prediction.

b. Find an experimental value for c. Don’t forget to determine the appropriate units.