What Force is Necessary to Submerge Mary in Fresh Water?

[coopertown]

What force is necessary to just barely submerge (push Mary under fresh water) Mary if her average specific gravity is 0.95 after taking a deep breath and her weight in air is 660 N?


F=mg ; Force of buoyancy=ρgV;



F=mg
660/9.8=mass of air
mass of air=67.3
force of buoyancy= 67.3 x 0.95
=63.94 Newtons

is this right?! i am panicking! physics is so hard omg. fluids are so difficult to understand! waaaaaaaaa

 

[ehild]

Do not panic! You have the formula for the buoyant force

Force of buoyancy=ρgV.

What do ρ, g, V mean?

ehild