The external and internal radii of the frictional faces in clutch are 100 mm and 60 mm, respectively. Determine the mean radius of friction face assuming the uniform pressure condition.

The external and internal radii of the frictional faces in clutch are

1.	The external and internal radii of the frictional faces in clutch are 100 mm and 60 mm, respectively. Determine the mean radius of friction face assuming the uniform pressure condition.
A.	60 mm
B.	70 mm
C.	82 mm
D.	78 mm
Answer» D. 78 mm