Theory of Machine
The example of rolling pair is

Ball and socket joint
Bolt and nut
Ball bearing and roller bearing
Lead screw of a lathe

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
Pitch point on a cam is

The point on cam pitch curve having the minimum pressure angle
Any point on pitch circle
Any point on pitch curve
The point on cam pitch curve having the maximum pressure angle

ANSWER DOWNLOAD EXAMIANS APP