A sphere of radius r falls at 0.1 m/s in a fluid. If it is replaced by a sphere of radius 2r in a fluid with double the viscosity, find vt.
Q1. A sphere of radius r falls at 0.1 m/s in a fluid. If it is replaced by a sphere of radius 2r in a fluid with double the viscosity, find vt.
Answer: 0.20 m/s
Explanation: Terminal velocity vt = (2gr²ρ)/(9η). Since vt is inversely proportional to η, doubling η while doubling r (r² factor of 4) results in 2vt.