Posted by Caitlyn on .
A freestyle skier hits the take off ramp with an initial velocity of 17.5 m/s with a purely vertical take off (90 degrees). What is the peak height that the skier will reach?
Can you fully explain to me how to get this answer?
I did the formula d=Vi*deltT+(1/2)(a)(t^2). To get time did 17.5m/s/9.81m/s=1.78s. Got the answer 46.69 but the answer is 15.56. I got 15.56 on one side of my equation so idk what I'm doing wrong.

Physics 
bobpursley,
You are using formulas without thinking.
at the peak height, the velocity is zero.
Vf=vi+at
0=17.5 + 9.8t
t= 1.78sec
hfinal=vi*time+1/2 g t^2
= 17.5*1.784.9(1.78^2)=15.6m