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Physics · PYQ NEET UG 2021
हिन्दीThe velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is \( \frac{d}{2} \), then the viscous force acting on the ball will be:
Correct answer · Option 4
\( \frac{Mg}{2} \)
Explanation
When the terminal velocity is reached, upward forces (viscous force \( F_v \) + buoyant force \( F_b \)) balance the downward gravitational force (\( Mg \)). Thus, \( F_v = Mg - V\sigma g = Mg - V(\frac{d}{2})g = Mg - \frac{1}{2}Mg = \frac{Mg}{2} \).
