- #1
Serge76982
- 6
- 0
Homework Statement
A woman is reported to have fallen about 139 ft from the 17th floor of a building, landing on a metal ventilator box that she crushed to a depth of 20 in. She suffered only minor injuries.
(a) Ignoring air resistance, calculate the speed of the woman just before she collided with the ventilator.
Your answer differs from the correct answer by 10% to 100%. ft/s
(b) Calculate her average acceleration while in contact with the box.
(c) Modeling her acceleration as constant, calculate the time it took to crush the box.
Homework Equations
[tex]x = x_0 + v_0t + \frac{1}{2}at^2[/tex]
[tex]v = v_0 + at[/tex]
The Attempt at a Solution
I'm stuck on the first part. I found a previous thread that had covered some of the solution methods so here goes.
x = 0 since we want her speed before she hit the ground and I converted x_0 to 1668inches (from 139ft). a is a constant that is -9.8m/s^2 or -32ft/s^2 (I will be using -32 since the answer calls for units in feet). That gives...
[tex] 0 = 1688 + v_0t + \frac{1}{2}(-32)t^2[/tex]
The other thread that I viewed mentioned setting [tex]v_0[/tex] to 0 and solving for t, although I'm not sure the purpose behind this or how would it help. What would you do after solving for t?
Last edited: