How high is the snow pile if a kid jumps off it and lands on the ground?

[Drizzy]

Homework Statement

The diagram shows a kid jumping off a snow pile into the grown that is also covered with snow. So the kid is jumping up and then lands on the ground.
https://scontent-arn2-1.xx.fbcdn.net/hphotos-xpf1/v/t34.0-12/12380374_1234806623215387_1066477107_n.jpg?oh=fe84392440a1ddbf0eebf557109d56ec&oe=5677CAA8
The question is: how tall is the snow pile if the ground is 0 m?

Homework Equations

S=v0t + (at^2)/2

The Attempt at a Solution

I am thinking that the kid is at its highest point when the velocity is zero and t=0.4. It takes 0.4 seconds up and also 0.4 seconds down to the level where the snow pile was at. so the snow piles height is from 0.8 seconds to 1,2 seconds. 1.2-0.8=0.4
s= -4*0.4 + (9.82 * 0,4^2)/2 = - 0,8144

What went wrong in my assumptions or solution?

 

[NascentOxygen]

If it's headed downwards, you are denoting this as a negative velocity, so g in your equation will likewise be negative.

 

[gneill]

Also, when the velocity is at its most negative point, that's when the kid reaches the top of the layer of snow that's on the ground, not the ground itself. Ponder the finish of the velocity vs time graph.