Sledge hammer physics, impact momentum

[acemet]

I need to find reasonable numbers for acceleration of a sledge hammer when striking a mass of rubber? A strong man can raise the hammer to 8 ft, then brings it down hard. What is reasonable velocity of the hammer before it contacts the mass of rubber? How much resilience is there, what is the velocity of the hammer as it leaves the rubber?

Thanks

 

[rock.freak667]

You can find in theory the velocity of impact by equation the potential energy of the hammer to the kinetic energy at the moment of impact.

The resilience you might need to look up for rubber.