Question

A body weighs 3.5 N in air and 2 N in water. How much buoyant force acts on the body?

Answer 1

Explanation:

buoyant force = weight of body in air - weight of body in water

buoyant force = 3.5 - 2 = 1.5 N

Answer 2

Buoyant force on the body = 1.5 Newtons

Explanation:

The upward force exerted by the fluid on the submerged object is called buoyant force.

Buoyancy force = weight of object in empty space − weight of object immersed in fluid

But the density of air is negligible compared to the solids and liquids. Hence, the weight of an object in air is approximately the same as its weight in empty space.

So Buoyancy force = weight of object in air − weight of object immersed in fluid

= 3.5 - 2

= 1.5 Newtons