Raindrop Terminal Velocity and Force Balance – Rankers Physics

Surface Tension and Viscosity: Practice Problem & Solution

Assertion (A): A raindrop after falling through some height attains a constant velocity. Reason (R): At constant velocity the viscous drag plus buoyant force is just equal to its weight.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution Explained:

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

Assertion (A) is true, as falling objects in a fluid reach terminal velocity when resistive forces balance gravity.

Reason (R) is true, stating the force balance condition for constant velocity: Weight = viscous drag + buoyant force. (R) correctly explains (A).

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Similar Practice Questions

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1. An object of mass m and density \(\rho\) is falling in a viscous liquid of density \(\frac{\rho}{4}\). When it attains terminal velocity, then viscous force acting on it will be:
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