Either face of the head is the hitting surface.
Hitting it with a hammer
Yes.
Hitting it with a very big hammer
push
It is kinetic energy.
a hammer
hitting the floor
The hammer technique is to grip it firmly in your strongest hand and strike the object you are hitting squarely and sharply.
nail forcing the hammer
It's a small hammer used in upholstery (before they had electric staplers ) One head is a round flat surface, about 3/4 " diameter and the other is the 'peen'.This is a flat short surface about 1/8 wide and 1/2" long meant for hitting small nails while you hold them.
I used to work in a Blacksmit's shop. We never discussed why he did this, but if I was hitting with the big hammer and he was hitting with the smaller hammer he would hit the anvil with the small hammer when he wanted me to stop hitting. I think it's just to keep pace. You can turn the metal, but I think it's just to keep pace.
Yes of course. It will be deformed