# Homework Help: Homework help! Volume in water

1. Nov 2, 2004

### skonstanty

A small sculpture made of brass (density = 8470 kg/m cubed) is believed to have a secret central cavity. The weight of the sculpture in air is 15.76N. When it is submerged in water, the weight is 13.86 N. What is the volume of the secret cavity?

2. Nov 2, 2004

### Tide

What exactly have you tried so far?

3. Nov 2, 2004

### skonstanty

I have just now started

4. Nov 2, 2004

### Gokul43201

Staff Emeritus
What property of the sculpture can you determine directly from the given data ?

5. Nov 2, 2004

### skonstanty

I am assuming I have to find the amount of displacement -- 15.76 - 13.86 = 1.9

6. Nov 2, 2004

### skonstanty

Oh, the density is = 8470

7. Nov 2, 2004

### Gokul43201

Staff Emeritus
Recall Archimedis ?

8. Nov 2, 2004

### skonstanty

Fb= bouyant force = F2 - F1 = mg

9. Nov 5, 2004

### rcgldr

What's in the secret cavity? Air, hydrogen, nothing, or maybe the other extreme, something just a bit lighter than water, like gasoline? This has to be known in order to answer the question.

10. Nov 5, 2004

### Justin Lazear

If it went from being filled with air directly to being submerged in water, I'd imagine what's in the cavity is air.

Not to mention that it'd be a ridiculous question if one couldn't assume such.

--Justin