Theory of Machine
Lower pairs are those which have

Two elements that permit relative motion
Elements of pairs not held together mechanically
Point or line contact between the two elements when in motion
Surface contact between the two elements when in motion

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Theory of Machine
In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon

Total lift, centre of gravity of the cam and cam speed
Total lift, total angle of lift, minimum radius of cam and cam speed
Radius of circular arc, cam speed, location of centre of circular arc and roller diameter
Mass of cam follower linkage, spring stiffness and cam speed

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