posted by peter on .
A pile driver of mass 1000kg,hits a post 3m below it.It moves the post 10mm.Assuming gravity=10m/s,what is the kinetic energy of the pile driver?
When it hits, the KE is the potential energy loss while falling 3 meters,
1000*10*3 = 30,000 J
How far it moves the post does not matter.