1. The problem statement, all variables and given/known data A stone is thrown horizontally from a cliff on a different planet with a speed of 10 m/s. The cliff has height 200m, and takes 4 s to hit the ground. Assume no air friction. What is the acceleration due to gravity on this planet. 2. Relevant equations Δy = v0t + 1/2 at2 3. The attempt at a solution I thought the initial vertical velocity would be 0 since it's thrown horizontally, so the first term of the equation disappears. And they give you t = 4, so I did 200*2/16 = 25 m/s^2. But apparently the answer is 5 m/s^2. Why?