Rectangle
Pentagon
Triangle
Parallelogram

## Theory of Machine When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a

Self-closed pair
Lower pair
Higher pair
Force-closed pair

## Theory of Machine When a point at the end of a link moves with constant angular velocity, its acceleration will have

Tangential component only
Coriolis component only

## Theory of Machine For an isochronous Hartnell governor (where r₁ and r₂ = Maximum and minimum radius of rotation of balls respectively, S₁ and S₂ = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)

(m.g - S₁)/(m.g - S₂) = r₂/r₁
S₂/S₁ = r₁/r₂
(m.g + S₁)/(m.g + S₂) = r₁/r₂
S₁/S₂ = r₁/r₂

## Theory of Machine The cam follower generally used in aircraft engines is

Spherical faced follower
Flat faced follower
Roller follower
Knife edge follower

## Theory of Machine In an open pair, the two elements of a pair

Have a line or point contact when in motion
Have a surface contact when in motion
Are not held together mechanically
Are kept in contact by the action of external forces, when in motion