Tree Bridges & Energy

This is a picture of my friend Sarah and I standing on a fallen tree that we found when we were hiking in Nuuanu. The tree was about fifteen feet off the ground and knowing this information would could have calculated our potential energy by using the equation PE = mv. Our potential energy while standing on top of the tree equals our kinetic energy at the ground if we had fallen off. So we could have figured out the velocity we would have been moving at when we hit the ground at if we had fallen by using the equation PE = KE, mv =(1/2)(m)(v)(v). Knowing our velocity at ground level, we could use the momentum formula, P = mv, to figure out what our momentum would be at the bottom of the fall. Impulse (J) is a force that acts for a certain amount of time and it represents change in momentum, J = (F)(t)= change in P= mv. So we know that the impulse exerted on us when we hit the ground is equal to mv. Luckily, we both have sick balancing skills and neither of us fell, which considering that the impulse would be rather large would have hurt a lot, but it is interesting to know that you can basically calculate how much a fall will hurt with only a very small amount of starting information (mass and height).