Question

A ball is falling freely in the air. After some time it
achieves a terminal velocity. This is
(a) Boltzmann’s law (b) Stokes' law
(c) Newton's law (d) Millikan's law

Answer 1

Answer: Newton’s law. Explanation: Newton gave the laws of motion .

Answer 2

(b) A ball is falling freely in the air. After some time it achieves a terminal velocity. This is Stokes' Law.

• Terminal Velocity is the velocity that is achieved by an object when it falls through a medium of fluid or a gas.
• Terminal velocity is directly proportional to the square of the radius of the sphere.
• Stokes proved that, if a small sphere of radius 'r' is falling with a terminal velocity 'v' through medium with coefficient of viscosity 'η', then the opposing force acting on the sphere due to viscosity is

                    F = 6πηrv