What is the height of a pole vaulter when she clears the bar?

[budugly77]

Conservation of energy??

This is suposed to be a problem concerning Conservation of Mecanical Energy however when i plug in the equation it does not work out.

A pole vaulter running at 10 m/s vaults over the bar. Her speed when she is above the bar is 1 m/s.
Neglecting air resistance and energy lost in the pole, what is her height when she clears the bar?

 

[SpaceTiger]

This is suposed to be a problem concerning Conservation of Mecanical Energy however when i plug in the equation it does not work out.

What are you getting and why do you think it doesn't work out?

 

[budugly77]

I am useing the equation ½mvi² + mgyi = ½mvf² + mgyf, however i am getting yf as 9 meters and that is too much for a pole vaulter so i am not sure what i am doing wrong

 

[SpaceTiger]

I am useing the equation ½mvi² + mgyi = ½mvf² + mgyf, however i am getting yf as 9 meters and that is too much for a pole vaulter so i am not sure what i am doing wrong

Your equation looks right. What did you use for vi, yi, vf, and yf? I'm getting about 5 m.

 

[dextercioby]

Please,DO NOT DOUBLE POST!The problem is really simple,as it doesn't mention about the pole's bending and the elastic energy which would convert in KE for the jumper.

Daniel.

 

[budugly77]

Thanks, when i re-did the equation i came out with about 5 also, so guess i was just typing it in wrong.