# Homework Help: Determing speed of water

1. Nov 29, 2009

### Beastegargoyl

1. The problem statement, all variables and given/known data
River Pascal with a volume flow rate of 4.7×105 joins with River Archimedes, which carries 1.1×106 , to form the Bernoulli River. The Bernoulli River is 130 wide and 30 deep.

What is the speed of the water in the Bernoulli River?
2. Relevant equations

3. The attempt at a solution
I attempted to guesses so far.
0.120 m/s was wrong
1.20 m/s was wrong

Thanks for all the help.
Jared

2. Nov 29, 2009

### tiny-tim

Welcome to PF!

Hi Jared! Welcome to PF!

(try using the X2 tag just above the Reply box )
Show us your full calculations, and then we can see what went wrong, and we'll know to help!

3. Nov 29, 2009

### Beastegargoyl

For vfr=4.7*105L/s

I used the equation 4.7*105/3900 equals 1.2m/s

Thanks for the help.
Jared

4. Nov 30, 2009

### tiny-tim

Hi Jared!

(just got up :zzz: …)
oh i see … you only used the volume flow rate of River Pascal.

The Bernoulli River contains the water of both River Pascal and River Archimedes.

5. Nov 30, 2009

### Beastegargoyl

@tiny-tim- Did you come up with an answer of .40m/s where that incportates both rivers?

Jared

6. Nov 30, 2009

### tiny-tim

I go 4.0 times something

what are the units of the problem?

7. Nov 30, 2009

### Beastegargoyl

4.7*105L/s and 1.1*106L/s. 130m wide and 30m deep.

The answer needs to be expressed in m/s.

8. Nov 30, 2009

### tiny-tim

oh, litres!

ok, then i make it .40m/s