Question

A 46 kg pole vaulter running at 10 m/s vaults

over the bar. Her speed when she is above the
bar is 0.9 m/s.
The acceleration of gravity is 9.8 m/s
2
.
Find her altitude as she crosses the bar.
Neglect air resistance, as well as any energy
absorbed by the pole.
Answer in units of m.

Answer 1

5.1 m

Step-by-step explanation:

The kinetic energy (most of it) 1/2 mv^2

is converted to Potential energy mgh

mgh = 1/2 mv^2 - 1.2 mv^2 (the underlined one is the KE at the top)

gh = 1/2 ( v^2 - v^2)

9.8(h) = 1/2 ( 10^2 - .9^2) shows h = 5.1 m