A ball is floating partially submerged in a liquid.

Which quantity equals the buoyant force acting on the ball?

volume of the ball above the surface
weight of the ball
volume of the ball below the surface
mass of the ball

Question

A ball is floating partially submerged in a liquid.

Which quantity equals the buoyant force acting on the ball?

 	
	volume of the ball above the surface
	weight of the ball
	volume of the ball below the surface
	mass of the ball

anonymous · Answer

Free body diagram and Newton's Laws will take care of this one.

anonymous · Answer

Hint: system is in equilibrium.

anonymous · Answer

To equate two quantities, they have to be of the same "dimensions".
The dimension of buoyant force is, naturally, force.
If you want, you can split force into components. 
$$ [F] = [M][L][T]^{-2}$$
Where F is force, M is mass, L is length and T is time.

If you do the same for the answers available, you'll find only one of them has the same dimension as force. This is a trick called dimensional analysis (not to be confused with unit conversion).

anonymous · Answer

so whats the answer?

anonymous · Answer

Which is the only answer that's a force?

anonymous · Answer

mass of the ball??

anonymous · Answer

Ooh, dimensional analysis. I like that too!

anonymous · Answer

No, mass isn't force.
Newton's (2nd?) law is
Force = mass times acceleration

anonymous · Answer

so answer would be the weight of the ball?

anonymous · Answer

Yep

anonymous · Answer

thanks i need help for one more.