Ask Your Teacher A 51-kg pole vaulter running at 11 m/s vaults over the bar. Her speed when she is above the bar is 1.1 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar.

6.11 N

Explanation:

Let,

m= mass of vaulter

Vi initial speed =11 m/s

Vf speed on pole (final) =1.1 m/s

Yi = initial height (when on ground)=o m

Yf = Height while crossing the pole =?

This problem can be solved by using conservation of energy rule;

KEi + PEi = KEf + PEf

==> 1/2 m+ mg = 1/2 m +mg

Initially the altitude of vaulter is zero i-e ==> PEi = mg = mg×0=0

==>1/2 m= /2 m +mg

==> m=m +2mg

cancelling m

==> = +2g

==> - =2g

==> =

==> =

==>  ==6.11N

newton's first law of motion

the answer is a 3.8cm

explanation: