Hello, first post. I hope that someone can help me with this. I will roughly summarize the problem, and what I've done thus far. 1. The problem statement, all variables and given/known data A lady was in an elevator that free-fell 6 feet and abruptly came to a halt. We had to determine a reasonable best case and a reasonable worst case value for the impact force that she experienced. The weight of the elevator is unknown and we are to find a value which I have not done yet. The woman weighs 140lbs. 2. Relevant equations x = x_0 + v_0*t + (1/2)a*t^2 F= ma 3. The attempt at a solution For the worst case I made the assumptions that all the weight was acting on one ankle and that the elevator hit the ground and came to a direct stop instantaneously. The forces I had acting were her body weight, the weight of the elevator, and the ground reaction force. I ended up with this: F = 0 = -623.63 (N, bodyweight acting in the neg. direction) -Welevator(Weight of the elevator) + GRF (Ground reaction force) Thus: GRF = Welevator +623.23N This was rather simple and once I find a weight of the elevator I should be fine. My issue comes in the Best case scenario, where I assumed that the body weight was equally distributed through both ankles and that the elevator decelerates. I had 1/2BodyWeight going through each ankle, the Welevator going through the middle, 1/2 of the GRF acting on each ankle. I used: x = xo + vo*t +1/2a*t^2 0 = 1.8288m + 0t + 1/2(-9.8m/s^2)*t^2 t = .61sec Not sure if I can use this here, and my problem is deciding how I would get the force from there. I'm assuming I would need a vf and a vi as well as the mass of the elevator which I mentioned before. Would Impulse=momentum work here? Any and all help would be greatly appreciated. Thanks in advance.