Calculus Question

Question

A stone is dropped from the edge of a roof, and hits the ground with a velocity of −100 feet per second. Assume the acceleration due to gravity is -32 feet per second squared. How high (in feet) is the roof? 

Answer 1

v=h'=-100= -32t

t=100/32= 25/8= 3.125 seconds

h(3.125)=0=-16t^2+ ho=-16(100/32)^2+ho= -50 ft+ho=0

ho= height= 50 feet