Question

A ball is thrown straight downward from the top of a tall building, with an initial speed of 30 ft/s. Suppose the ball strikes the ground with a speed of 190 ft/s. How tall is the building? Acceleration is -32 ft/s squared

Answer 1

V^2 = Vo^2 + 2g*h
h = (V^2-Vo^2)/2g
h = ((190)^2-(30)^2)/64 = 550 Fi.

Answer 2

height = -16t^2 -30t + d, where d is the height of the building
d(height)/dt = velocity = -32t - 30
-190 = -32t - 30
32t = + 160
t = 5

at t = 5 , height = 0
0 = -16(25) - 150 + d
550 = d