A plate of area 100 cm^2 is placed on the upper surface of castor oil 2mm thick . Taking the coefficient of viscosity to be 15.5 poise. Calculate the horizontal force necessary to move the plate with a velocity of 3 cms^(-1) ?

A plate of area 100 cm^2 is placed on the upper surface of castor oil

1.	A plate of area 100 cm^2 is placed on the upper surface of castor oil 2mm thick . Taking the coefficient of viscosity to be 15.5 poise. Calculate the horizontal force necessary to move the plate with a velocity of 3 cms^(-1) ?
Answer» Solution :`A = 100 cm^2 , dv = 0-3 = - 3 cm s^(-1) , dx = 2 mm, ETA = 15.5 ` poise From F = `-eta (dV)/(dx) , F = -15.5 xx 100 xx (-3)/(0.2) = 232.5 xx 10^(2) ` DYNE `= 232.5 xx 10^(-3)` N