The device shown consists of a disk that is rotated by a shaft . The disk is positioned very close to a solid boundary. Between the disk and the boundary is viscous oil. a. If the disk is rotated at a...

The device shown consists of a disk that is rotated by a shaft . The disk is positioned very close to a solid boundary. Between the disk and the boundary is viscous oil.

a. If the disk is rotated at a rate of 1 rad/s, what will be the ratio of the shear stress in the oil at r = 2 cm to the shear stress at r = 3 cm?

b. If the rate of rotation is 2 rad/s, what is the speed of the oil in contact with the disk at r = 3 cm?

c. If the oil viscosity is 0.01 N∙s/m²
and the spacing y is 2 mm, what is the shear stress for the conditions noted in part (b)?