Net Force on Ball at Terminal Velocity – Rankers Physics

Fluid Dynamics: Practice Problem & Solution

A small ball of mass \(m\) and density \(rho\) is dropped in a viscous liquid of density \(\rho_0\). After sometime, the ball falls with constant velocity. The net force acting on the ball after it attains constant velocity, will be:
\(mg\left(\frac{\rho_0}{\rho}-1\right)\)
\(mg(\rho - \rho_0)\)
\(mg\left(1-\frac{\rho}{\rho_0}\right)\)
Zero

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Fluid Dynamics. Understanding the underlying formula is key to arriving at the correct answer below:

When a body falls with constant velocity (terminal velocity), its acceleration is zero. Thus, by Newton's second law, the net force on it is zero.

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