CBSE Class 9 Science Question 20 of 33

Gravitation — Question 20

Back to all questions
20
Question

Question 20

Why a block of plastic when released under water come up to the surface of water?

Answer

When plastic is immersed in water, two forces act on it:

  1. Gravitational force or its weight in vertically downward direction
  2. Buoyant force in vertically upward direction.

As the density of plastic is less than that of water, the buoyant force is greater than its weight. Hence, the plastic comes up to the surface.