Question

A ball has a diameter of 3.89 cm and average density of 0.0842 g/cm3. What force is required to hold it completely submerged under water?

Answer 1

find the volume of the ball (sphere)

mass = volume * density

forces on the ball
... gravity ... downward ... m * g
... buoyancy ... upward ... equal to mass of water displaced times g

(ball volume) * (water density) * g =
... [(ball mass) * g] + (hold down force)