A metal block of area `0.10m^(2)` is connected to a 0.010 kg mass via a string that passes over an ideal pulley (cosidered massless and frictionless). As in figure. A liquid with a film thickness of 0.30 mm is placed b etween the block and the table. when released the block moves to the right with a constant speed of `0.085ms^(-1)`. find the coefficient of viscosity of the liquid.

Explanation

Surface area= A = `0.30 m^(3)`
Mass `= m = 0 . 016 kg`
Tension in the string `= T = mg = 0.016 xx 9.8 = 0.1568 N`
i.e. ` " " F = 0.1568 N`
Speed of the plate ` = dv = 0.170 m//s`
Thichness of the lubricant film = `dx =0.60 xx 10 ^(-3) m `
Coefficient of viscosity `eta ? `
` " " F= eta A ( dv)/(dx)`
` eta = ( Fdx)/( Adv) = ( 0.1568 xx 0.60 xx 10 ^(-3))/( 0.30 xx 0.17)= 1.8 xx 10 ^(-5) Ns m^(-2)`