Question

A cube having sides of length 7.0cm is made of iron. The cube is dropped into a swimming pool where it immediately sinks and then rests on the horizontal bottom surface. a) what is the value of the normal force exerted by the pool floor on the block?b) how would the buoyant force that you found during your solution to part a have changed if the black had been made of copper instead of iron?

Answer 1

Answer 2

Volume of iron cube = (7^3) = 343cc.
It is displacing 343cc. of water, with a mass of 343g., or 0.343kg.
The buoyant force on it is (0.343 x g) = 3.3614N.
Iron density is around 7.87g/cc., so iron mass = (7.87 x 343cc) = 2,699.41g., or 2.69941kg.
Force downwards towards bottom = (2.69941 x g) = 26.45N.
a) Subtract the upward buoyant force of 3.3614N., and normal force = 23N.
b) The buoyant force does not change, only the normal force from the pool bottom.