Question

Two equal sized cubes that have different masses are held by strings so that they are submerged in water at different depths as illustrated in the figure below. 3 kg 1 kg Compare the following: i. The buoyant force exerted by the water on the 3 kg cube to the buoyant force exerted on the 1 kg cube.

Answer 1

Here the importance concept to tackle out these type of problems is that the condition of buoyancy which is given as,

Fb = pgV

Where,

P = density of fluid

g = gravity

V = A × h = volume of fluid displaces by the body.

So depending upon these concepts lets answer the question as,

I) both will experience equal buoyant force

Because two cubes have same volume and are fully immersed so they will displace same volume of water and then will experiance same buoyant force.

II) tension in the string holding 3kg cube will be greater than the tension in the string holding 1 kg cube.

Because as here buoyant force is same for both of them so that tension will be directly related to their masses hence heigher the mass of 3kg cube will have heigher the tension in its string.

III) the pressure exerted on the bottom surface of 3kg cube by the water will be less than the pressure exerted on the bottom surface of the 1 kg cube.

Because 1kg cube is deeper in liquid where pressure is larger.