- #1

- 13

- 0

## Homework Statement

Spiderman steps from the top of a tall building. He falls freely from rest to the ground a distance of h. He falls a distance of h/4 in the last interval of time of 1.2 s of his fall.

What is the height h of the building?

The acceleration is constant -g.

## Homework Equations

y(t) = y(0) + v(0)t - 1/2gt^2

v = v(0) - gt

v^2 = v(0)^2 - 2g(y-y(0))

## The Attempt at a Solution

I found the average velocity of the final interval of time to be (h/4)m / 1.2s = (h/4.8)m/s.

I know the average velocity occurs at half the displacement; so, I used this velocity as the initial velocity for another displacement of h/8 (or half the distance of the final interval).

Then I tried using g = -9.8m/s^2, v(0) = -(h/4.8)m/s, y(0) = (h/8)m, and y = 0 to find the time spiderman takes to travel that distance, but I cannot do that without figuring out h, my original target.

Please help.