MHT CET202121 Sep 2021Morning ShiftPhysicsMechanical Properties of FluidsActual
The velocity of a small ball of mass ' M ' and density ' d ₁ ' when dropped in a container filled with glycerin becomes constant after some time. If the density of glycerin is ' d ₂ ', the viscous force acting on the ball is ( g = acceleration due to gravity)
Options
- AMg d ₁ ~d ₂
- BMgd ₁ ~d ₂
- CMg ( d ₁- d ₂ )
- DMg (1- d ₂ ~d ₁ )
Correct answer
D. Mg (1- d ₂ ~d ₁ )
Step-by-step solution
Since the velocity is constant, the net force acting on the ball is zero. aligned & F _ V + F _ B = Mg & F _ V + Vd ₂ ~g = Mg aligned F _ v + M d ₁ ~d ₂ ~g = Mg F _ V = Mg (1- d ₂ ~d ₁ )