A pole-vaulter just clears the bar at 4.24 m and falls back to the ground. The change in the vaulter's potential energy during the fall is -3500 J. What is his weight?

3 answers

Gee, I'm disappointed. I thought people in Ypsilanti were smart enough to know the difference between School Subject and the name of the school.
m g h = 3500

m * 9.81 * 4.24 = 3500
PE = m * g * h ; Weight = m * g ; Remember, Mass is not Weight!

3500 = m * 9.81 * 4.24
3500 / (9.81 * 4.24) = m
m = 84.15 g

W = m * g = 84.15 * 9.81 = 824 N

Answer: 824 N