# Need some Help

1. Apr 9, 2005

### imnotsmart

I have two more questions for anyone can help....
1. A frog in a hemispherical pod finds that he just floats without sinking in a fluid of density 1.25 g/cm3. If the pod has a radius of 9.00 cm and negligible mass, what is the mass of the frog?
2. A cowboy at a dude ranch fills a horse trough that is 1.6 m long, 60 cm wide, and 40 cm deep. He uses a 1.9 cm diameter hose from which water emerges at 1.4 m/s. How long does it take him to fill the trough?

2. Apr 9, 2005

### dextercioby

For the first problemINT:The buoyancy force must be equal to the gravity force...

For the second:what is the colume of the trough?What is the flow through the hose...?

Daniel.

3. Apr 9, 2005

### imnotsmart

I still don't understand how you begin the problem....do you divided 9 cm by 1.25 g/cm^3?

4. Apr 9, 2005

### marlon

Firstly, you must understand the definition of The buoyancy force. Do you know what that is and how to calculate it ???

marlon

5. Apr 10, 2005

### imnotsmart

Anyone help?

6. Apr 10, 2005

### dextercioby

Daniel.

7. Apr 10, 2005

### imnotsmart

Yeah, the pod partially submerged in the fluid experiences the bouyant force equal in magnitude to the weight of the fluid displaced by the pod.
To calculate it B=PfluidVg=wfluid ?

Last edited: Apr 10, 2005
8. Apr 10, 2005

### dextercioby

$F_{B}=\rho_{fluid}V_{body}g$...

And u need to know the volume of the immersed body.

Daniel.

9. Apr 10, 2005

### imnotsmart

how do you find the volume of the immersed body?

10. Apr 10, 2005

### dextercioby

I can only assume that all the hemisphere is immersed.The problem is not to explicit,so you have to make assumptions,in order to get a result.

Daniel.