# Consservation of energy problem

1. Aug 4, 2009

### Elmnt

1. The problem statement, all variables and given/known data

A 50 kg skier starts from rest at a height of H = 25 m above the end of the ski-jump ramp. As the skier leaves the ramp, his velocity makes an angle of 28° with the horizontal. Neglect the effects of air resistance and assume the ramp is frictionless.

What is the maximum height h of his jump above the end of the ramp?

http://www.webassign.net/hrw/hrw7_8-39.gif

2. Relevant equations

I was using the conservation of energy equation:$$\textit{K_{i}+U_{i}+W = K_{f}+U_{f}}$$
but I am getting stuck. I'm just not sure how to approach this problem. Using the initial kinetic energy as 0 and the initial potential energy as mass*gravity*height and that equals the kinetic energy plus the potential energy due to gravity at the height above the ramp. I don't know what the kinetic energy would be at this point so I cannot solve for the height. Am I looking at this correctly?

2. Aug 4, 2009

### rl.bhat

When the skier is at H = 25 m, his vertical velocity is given by v^2 = 2gH.
Since ramp is frictionless, the same vertical velocity will be there when he leaves the ramp at an angel 28 degrees. When he is at the highest point his vertical velocity will be zero. Now find h.

3. Aug 4, 2009

### Elmnt

Thank you for your help!