# Homework Help: Force exerted by water in a U-shaped tube

1. Aug 27, 2011

### Dansuer

1. The problem statement, all variables and given/known data
In a U-shaped tube, water is flowing with velocity v. The flowing rate is u, and it's constant. What force does the water exert on the wall of the tube.

2. Relevant equations

F = dp/dt

u = m/t

3. The attempt at a solution
The change in momentum is
$mv - (-mv)$

or

$2uv \Delta t$

so

$F = 2uv$

is this correct?

Last edited: Aug 27, 2011
2. Aug 27, 2011

### vela

Staff Emeritus
Yes, that's correct.

3. Aug 27, 2011

### Dansuer

Thanks a lot !