Question

A body of mass 3.5 kg displaces 1000 cm³ of water when fully immersed inside it. Calculate:

1. the volume of body,
2. the upthrust on body and
3. the apparent weight of body in water. 

Answer 1

Mass of body = 3.5 kg

Weight of the body = 3.5 kgf

Volume of water displaced when body is fully immersed = 1000 cm³

(i) Volume of body when fully immersed in liquid = Volume of water displaced

∴ Volume of body = 1000 cm³ or 0.001 m³

(ii) Upthrust on body = Volume of body × Density of water × g

= 0.001 × 1000 × g

= 1 kgf

(iii) Apparent weight = True weight - Upthrust

= 3.5 - 1

= 2.5 kgf