Question

A stone is dropped from the edge of a roof, and hits the ground with a velocity of -185 feet per second. How high (in feet) is the roof?

Answer 1

Vf^2 = Vi^2 + 2*a*d Vf = -185 Vi = 0 a = -9.8 so for d

Answer 2

The height of the roof is 534.8 feet.

Explanation:

Let h be the height of the roof.

We know the formula

`v^2-u^2=2gh`

Since, the stone is dropped from the edge of the roof hence, the initial velocity should be zero. Thus, u = 0

`v^2-0=2gh\\h=(v^2)/(2g)`

Now, we have

v = -185 feet per second

g = 32 feet per square second

On substituting these values, we get

`h=((-185)^2)/(2* 32)\\\\h=534.8`

The height of the roof is 534.8 feet.