$7\mathrm{.}5$ Write the Reynolds equation for the situations shown below. The circles represent infinitely long cylinders, and all velocities are in relation to a

$225/703$

fixed coordinate system. The lubricant can be assumed to be Newtonian, incompressible, and isoviscous.

$($a$)$

$($c$)$

$($b$)$

$($d$)$