What forces does a person experience after falling from a sixth storey building?If someone falls from a sixth storey building, with what force will he land? By this I mean to say that if he weighs 50 kg and was initially at rest before falling, which implies it was a free fall. We can easily calculate the velocity and momentum as we know the acceleration due to gravity... but with what force he will land?

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fonfonvkdpf · Accepted Answer

It is the not the   m  v that kills you, but the             d      p              d      t      The ground will eventually bring you to rest, in a time   δ  t. This can be very large for soft materials, like a bouncy castle or sponge, or very short for incompressible materials like concrete and steel.Your momentum change   Δ  p from the instant before impact and rest is   0  −  m      v          f      i      n      a      l        =  −  m      v          f      i      n      a      l      . Hence, the ground exerts a force   F on you:  F  =            d      p              d      t        ≈  −            Δ      p              δ      t        ,which is negative as it needs to decelerate you to bring you to rest.      v          f      i      n      a      l       is calculated with the usual suvat equations.What is the actual physical nature of the force? The resistance of objects to being deformed, hence the   δ  t dependence that I mentioned earlier. In essence this boils down to molecular bonds so it&#039;s electromagnetism.

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