# Energy in the punch

1. Dec 25, 2003

### Nim

Anyone have an idea of how much energy is transfered to someone or something when someone punches them or it? I know this can vary a lot, but does anyone have any numbers? I came across one website that said something like the "average force of a focused Sieken (punch)" delivers 700 foot-pounds, whatever a Sieken punch is, I don't know. I came across another website that talked about some people who recorded the energy delivered to a punching bag by their boxing team. I wasn't familier with the units though, I think it was "1,064 pound impulses" from one of their guys.

2. Dec 26, 2003

### Bob3141592

It should be easy to measure, or estimate if you're familair with some common equipment. First, remember that
$$E = \frac{1}{2}mv^2$$
Now, assume a punching bag of mass m hanging motionless being hit with a punch (and I'm thinking of one of those big cylindrical sand filled punching bags, not the small teardrop shaped ones). How fast is the bag moving after it's hit with a punch? That's all you need to know.

Last edited: Dec 26, 2003