Question

A body whose volume is 100 cm³ weighs 1 kgf in air. Find its weight in water.

Answer 1

Volume of body = V = 100 cm³ = 10^-4 m³

Weight of body in air = 1 kgf

Density of water = p_w = 1000 kgm³

We know volume of water displaced = Volume of body

= V = 10^-4 m³

Upthrust = Weight of water displaced by body = Vp_wg

= 10-⁴ x 1000 x g .

= 10-¹ kgf =0.1 kgf

Weight of body in water=Weight of body in air – Upthrust

= 1-0.1 =0.90 kgf