A friction clutch has an outer diameter D and an inner diameter d. The axial force F necessary to produce a certain torque T and a pressure p is de...

A friction clutch has an outer diameter D and an inner diameter d. The axial force F necessary to produce a certain torque T and a pressure p is desired. Two methods are generally available to solve the problem, depending on the clutch construction. If the discs are rigid, the most wear will occur first in the outer areas, since there the friction work is greater. After a certain amount of wear has taken place, the pressure distribution will be modified to allow for uniform wear. This is the basis of the first solution method. In the other construction method, springs are used to obtain uniform pressure over the area. This is the assumption of uniform pressure used in the second solution method. The text presents equations to calculate the axial wear and the torque of the clutch. What is the main difference between the equations for uniform wear and uniform pressure?

The equations for uniform wear and uniform pressure are the same.
The equations for uniform wear and uniform pressure have different variables.
The equations for uniform wear and uniform pressure have different constants.
a) I
b) II
c) III
d) II and III
e) I and II