1) The terminal speed of a sphere of gold (density =19.5 kg/m3) is 0.2 m/s ina viscous liquid (density =1.5 kg/m3) , find the terminal speed of a sphere of silver (density= 10.5 kg/m3) of the same size in the same liquid A) 0.4 m/s B) 0.133 m/s C) 0.1 m/s D) 0.2 m/s Answer: Option CExplanation:Terminal velocity, $v_{T}=\frac{2r^{2}(d_{1}-d_{2})g}{9\eta} $ $\frac{v_{T_{2}}}{0.2}=\frac{(10.5-1.5)}{(19.5-1.5)} \Rightarrow v_{T_{2}}=0.2\times\frac{9}{18}$ $\therefore$ $v_{T_{2}}= 0.1 m/s$
