What is the shear rate s1 when a lotion is rubbed onto the s

What is the shear rate (s^-1) when a lotion is rubbed onto the skin with a relative rate of motion between fingers and skin about 11 cm s^-1, and the film thickness is about 64 micrometer? Enter your result as integer, without decimal places and without units.

Solution

The shear rate is the difference in velocity between the different layers and can here be calculated as the velocity of the top plate (the bottom plate does not move) and the distance between the plates, i.e., shear rate is = v/h.

thickness=64

speed relative-11cm/sec=110000micrmeter/sec

=(110000/64)

=1719