Caculation of force exerted by water

[sadowski777]

Hi,

I was standing in a river and I'm curious how much force it was exerting on my leg. I'm not sure how to do this calculation. Here's what I know:

F=ma
if the final velocity is zero, F=mv/t

I'll assuming I was standing in 1ft of water, my leg is 36in^2, and the water is traveling at 4mph.

It doesn't make sense that the force exerted over 2 seconds would be different then the force exerted over 4 seconds.

Any suggestions or help?

Thanks

 

[A.T.]

You need this:
http://en.wikipedia.org/wiki/Drag_equation
You can approximate the leg as a cylinder:
http://scienceworld.wolfram.com/physics/CylinderDrag.html

 

[sadowski777]

Excellent. Thank you very much.