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A hammer of mass m falls from rest off of a roof and drops a height H onto your head.
a) Assuming that the tool is in actual contact with your head for a time △t before it stops and slides off, what is the algebraic expression for the average force it exerts on your skull while stopping?

Respuesta :

carlosego
For conservation of energy we have to:
 mgH=mv²/2 
 Clearing
 v=sqrt(2gH)
 Then, by definition 
 F=Δp/Δt= Δ(mv)/ Δt=m Δ(v)/Δt= 
 =m[sqrt(2gH)-0]/Δt= m[sqrt(2gH)]/ Δt
 the answer is
 F=m[sqrt(2gH)]/ Δt