# Homework Help: Applying the momentum equation

1. Mar 13, 2013

### MMCS

I have attached the question and working out as i would lose the format. The answer i arrive at is innacurate by 2000N approx from the correct answer, If anybody could look at my working out and point out any mistakes i would appreciate it as i have been on this for hours and cant see the mistake

Thanks

#### Attached Files:

• ###### working.png
File size:
45.4 KB
Views:
135
2. Mar 13, 2013

### TSny

A couple of things: Did you use .355 instead of the given .335 for the volume flow rate when calculating the speeds c1 and c2?

In the Bernoulli equation, did you get the signs of the velocity terms correct?

I'm not sure, but shouldn't you use the mass of just the water rather than the total mass of water and pipe (240 kg) for the gravity force on the water in the equation for Fy?

[EDIT: To me, the question is not very clear as to whether the pipe bends upward or downward.]

[EDIT: Also, the pressure given at the inlet is given as "static".]

Last edited: Mar 13, 2013