Question

A stone is thrown upward from ground level. With what minimum speed should the stone be thrown so as to reach a height of 64 feet?

Answer 1

x = x0 + v0t + a/2 t^2.
64 = 0 + v0t -9.8/2 t^2. (1)
v0 is what you want. You must solve for time first.
V = v0 + at.
0 = v0 -9.8t . (2)
Therefore v0 = 9.8 t. Put this into (1) to find t and then plug that time into either equation to find v0.

Answer 2

So 64 = 9.8t^2 - 4.9t^2 .

Answer 3

9.8t is for meters, but i'll change the formula for feet and solve it myself. thank you!

Answer 4

Sure thing.