# Archimeds principle

1. Nov 5, 2008

### luckyme

1. The problem statement, all variables and given/known data

a string supports a solid copper block off mass 1kg(density= 9*103 kgm3) which is completely immersed in water ( density= 1*103kgm3). calc the tension in the string.
2. Relevant equations

don`t know

3. The attempt at a solution

no clue.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 5, 2008

### Staff: Mentor

luckyme, we do not do your work for you here on the PF. We can offer tutorial assistance, but you *must* attempt to do the work first. Your other threads with no attempts at working the problems have been deleted. You may re-post them if you show some work.

Now, what are the two components that go into the tension on the string? The weight of the block (in air), and what?

3. Nov 5, 2008

### luckyme

the question doesnt say abt surface area. would you work out the upthrust first . dont know volume of water either, dont undstand the componetns.

4. Nov 5, 2008

### Staff: Mentor

You are given the mass and density of the block. How would you use those to calculate the volume of the block? Use the units to keep your calculation straight.

5. Nov 5, 2008

### luckyme

maybe divide by a cubic meter.

6. Nov 5, 2008

### Staff: Mentor

Don't guess. Use the quantities given, and look at their units. Carry the units along in your calculations along with the numbers, to be sure that you are doing the correct things to get the answer you want.

The units of mass are kg.

The units of density are kg/m^3.

The units of volume are m^3.

What equation could you write to get the volume from the density and mass?

V = ? / ?

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