A metal block of base area 0.2 m^2 is connected to a 0.02 kg mass via a string that passes over an idealpulley as shown in figure. A liquid film of thickness 0.6 mm is placed the block and the table. When released the block moves to the right with a constant speed of0.17 m//s . The co-efficient of viscosity of the liquid is

A metal block of base area 0.2 m^2 is connected to a 0.02 kg mass via

1.	A metal block of base area 0.2 m^2 is connected to a 0.02 kg mass via a string that passes over an idealpulley as shown in figure. A liquid film of thickness 0.6 mm is placed the block and the table. When released the block moves to the right with a constant speed of0.17 m//s . The co-efficient of viscosity of the liquid is
Answer» `3.45xx10^3 PA. s` `3.45xx10^-2 Pa. s` `3.45xx10^-3 Pa. s` `3.45xx10^2 Pa.s` Solution :Velocity GRADIENT of the liquid film between the block and the table `=v/x[x=` thickness of film] `therefore`Viscous force, `F=eta A v/x` or, `eta=(MGX)/(AV) =(0.02xx9.8xx(0.6xx10^-3))/(0.2xx0.17)` `=3.46xx10^-3 Pa. s`