How much steel is needed to suspend a balloon at 50 ft below sea level?

[Don654321]

I need some help with a calculation. I am trying to calculate how much steel in weight would be needed to suspend a ball(essentially a balloon) 12in in diameter full of air at 50 ft below sea level, in sea water. I am not the best at physics and I think I have an idea but wanted a good opinion. Does not have to be exact just a good estimation.

 

[russ_watters]

Welcome to PF!

The best way to learn is to learn by doing. So take a shot. Some hints to get you started: do you know the equation for buoyancy? Density of water and steel?

 

[Don654321]

seawater=1025 kgm3 Steel = 7850 kgm3 and I am not exactly sure which formula to use?

 

[russ_watters]

Use the equation for buoyancy.