Question

Question 72:
If two equal weights of unequal volumes are balanced in air, what will happen when they are completely dipped in water ? Why ?

Lakhmir Singh Physics Class 9

Answer 1

Answer:

The body with the lesser volume will undergo less reduction in weight than the body with more volume.

Explanation:

When the bodies are immersed in water, they will displace the water equal to their Volumes. The buoyant force that will act on the bodies will be equal to the weight of the water displaced. So the body with more volume will displace more water, its weight will be more therefore the buoyant force acting upwards on the body will be more. Therefore there will be greater reduction in the weight of the body with more mass.

Hope this helps.

Answer 2

The weight with more volume will experience a large decrease in weight.

Explanation:

• Buoyant force acts on a body immersed in a liquid.
• Therefore, the buoyancy acts on both these weights with unequal volumes.
• Buoyant force is given by the equation $F=V*D*g$
• Here, V is volume of immersed body, D is density of the liquid in which body is immersed, g is acceleration due to gravity
• for these two equal weights, force of buoyancy is proportional to volume of the weight as density and acceleration due to gravity is same for both the bodies.

hence,  $F$∝$V$, Therefore, the weight with more volume will experience a large buoyant force and thus a large decrease in its weight.