Question

The weight of a piece of stone in air is 100N and its weight in water is 80 N. Calculate the

Buoyancy of water​

Answer 1

Weight difference =

150-100 = 50 N = Buoyant force of water

Buoyant Force in water(Fb) = density of water x g x volume of body(Vb)

50 = 1000 x 9.81 x Vb

Vb = 50/9810 cubic meter

Now, in air
Weight of body = mg = 150 N

Mass of body,m = 150/9.81 Kg

So,
Density of body = m/ Vb

= 150/9.81 ÷ 50/9810

= 3000 kg per cubic meter

Specific gravity of body = density of body ÷ density of water

= 3000 ÷ 1000

Specific gravity of body = 3.