Question

A stone is dropped from the edge of a roof, and hits the ground with a velocity of -145 feet per second. How high (in feet) is the roof

Answer 1

Ke = (1/2) m v^2 = (1/2) m (145^2)
pe = m g h where g = 32.2 in ft/seconds units
32.2 m h = (1/2) m (145^2)
h = 326 feet

Answer 2

vf^2=2gh

solve for h, in feet

g= 32ft/s^2

Answer 3

Hey Bob, I was wondering why gravity is 32m/s^2 instead of 9.8m/s^2. Can you explain why this is?

Answer 4

Check the units m/s^2 and ft/s^2