Question

A spherical body falls through a viscous liquid and reaches terminal velocity. At this point, which condition is satisfied?

Options

• Gravitational force equals surface tension

• Buoyant force equals gravitational force

• Gravitational force equals the viscous drag force

• Kinetic energy equals potential energy

Answer 1

Gravitational force equals the viscous drag force

Explanation:

Terminal velocity is reached when the net downward gravitational force equals the upward viscous drag force (Stokes' law). At this point, there is no net force on the sphere, so it moves at a constant velocity with zero acceleration.