- #1
Saladsamurai
- 3,020
- 7
[SOLVED] Stupid Buoyancy, this is getting ridiculous.
A hollow sphere of inner readius 8cm and outer radius 9cm floats half submerged in a liquid of density 800kg/m^3. What is the mass of the sphere and the density of the material it is made from.
[tex]\sum F=0[/tex]
[tex]\Rightarrow mg-F_b=0[/tex]
[tex]\Rightarrow m=\rho*\frac{V_s}{2}[/tex]
Now for the Volume do I use [tex]\frac{4}{3}\pi r^2[/tex]
or
[tex]\frac{4}{3}\pi (r_2^2-r_1^2)[/tex] ?
I thought it would just be the outer radius that was important here. But I have tried BOTH ways and both come out wrong...so I am messing something else here...are there only 2 Forces here?
The answer for mass should be 1.2 kg
ahhhhhhhhhhhhhh!
Casey
A hollow sphere of inner readius 8cm and outer radius 9cm floats half submerged in a liquid of density 800kg/m^3. What is the mass of the sphere and the density of the material it is made from.
[tex]\sum F=0[/tex]
[tex]\Rightarrow mg-F_b=0[/tex]
[tex]\Rightarrow m=\rho*\frac{V_s}{2}[/tex]
Now for the Volume do I use [tex]\frac{4}{3}\pi r^2[/tex]
or
[tex]\frac{4}{3}\pi (r_2^2-r_1^2)[/tex] ?
I thought it would just be the outer radius that was important here. But I have tried BOTH ways and both come out wrong...so I am messing something else here...are there only 2 Forces here?
The answer for mass should be 1.2 kg
ahhhhhhhhhhhhhh!
Casey