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

A rock is thrown vertically upward from the edge of a cliff. The rock reaches a maximum height of 18.6 m above the top of the cliff before falling to the base of the cliff, landing 6.60 s after it was thrown. How high is the cliff? Assume gravity= 9.8m/s

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**2. Relevant equations**

Vy_{f}=Vy_{o} + at

Y=Y_{o} + 1/2(Vy_{o}+Vy_{f})t

Y=Y_{o} + Vy_{o}t + 1/2at^{2}

Vy_{f}^{2}=Vy_{o}^{2}+ 2a(y-y_{o})

**3. The attempt at a solution**

I don’t know where to start. I must figure out initial speed and the difference between the cliff and the max height. Is the initial position 0 at the height of the cliff or at the max height? Do I care that when the ball reaches the max height the speed is 0?

http://ift.tt/1dJsj9r