A metal block of area \(0.10~\text{m}^{2}\) is connected to a \(0.010\) kg mass via a string that passes over an ideal pulley (considered massless and frictionless), as in the figure below. A liquid film with a thickness of \(0.30\) mm is placed between the block and the table. When released the block moves to the right with a constant speed of \(0.085\) m/s. The coefficient of viscosity of the liquid is:

          
1. \(4.45 \times 10^{-2}~\text{Pa-s}\)
2. \(4.45 \times 10^{-3}~\text{Pa-s}\)
3. \(3.45 \times 10^{-2}~\text{Pa-s}\)
4. \(3.45 \times 10^{-3}~\text{Pa-s}\)

The terminal velocity of a copper ball of radius \(2.0\) mm falling through a tank of oil at \(20^{\circ}\text{C}\) is \(6.5~\text{cm/s}.\) What is the viscosity of the oil at \(20^{\circ}\text{C}\)? (Density of oil is \(1.5\times 10^{3}~\text{kg/m}^3,\) the density of copper is \(8.9\times10^{3}~\text{kgm}^{-3})\)
1. \(7.9\times 10^{-1}~\text{kgm}^{-1}\text{s}^{-1}\)
2. \(8.9\times 10^{-1}~\text{kgm}^{-1}\text{s}^{-1}\)
3. \(9.9\times 10^{-1}~\text{kgm}^{-1}\text{s}^{-1}\)
4. \(8.8\times 10^{-1}~\text{kgm}^{-1}\text{s}^{-1}\)