Explain the term: (i) Slip (ii) Creep

Slip: The forward motion of the driver without carrying the belt with it or forward
motion of the belt without carrying the driven pulley with it, is called slip of the belt.
Slip reduces velocity ratio and also power transmission capacity of the belt drive. Less
slip in the belt drive is desirable.
When belt is transmitted power from driver to driven pulley, there is a loss of motion
due to insufficient frictional grip and therefore the speed of driven pulley is less than

Draw neat diagram of ‘scotch yoke mechanism’? Explain its constructional features in brief.


Constructional Features of Scotch Yoke Mechanism:
[1] In this mechanism, two sliding pairs and two turning pairs are used. So it is an
inversion of Double Slider Crank Chain Mechanism.
[2] It consists of following types of links with relative motion as mentioned below;
Link 1 (B) – Fixed Link – Guide the Frame
Link 2 – Crank – Turning Motion – Rotates about Point B in Link 1
Link 3 - Slider -Sliding Motion
Link 4 – Fixed Link – Frame – Reciprocating Motion
[3] The inversion is obtained by fixing either the Link 1 or Link

State the functions of clutches

[1] To engage and disengage output shaft with the engine shaft as and when required.
[2] To engage shafts very smoothly without much slipping of friction surfaces.
[3] To transmit power from engine shaft to output shaft without loss.
[4] To engage the shafts smoothly without noise and jerk

List any four applications of ‘cam’ and ‘follower’.

Applications of Cam and Follower:
[1] Operating the inlet and exhaust valves of internal combustion engines
[2] Used in Automatic attachment of machineries, paper cutting machines
[3] Used in Spinning and weaving textile machineries.
[4] Used in Feed mechanism of automatic lathes etc.
[5] Used in Diesel Fuel Pumps.
[6] Used in printing control mechanism
[7] Used in wall clock
[8] Used in feed mechanism of automatic lathe.

State the relation between relative velocity and motion of link in mechanism.

Relation between Relative Velocity and motion of link in mechanism:
The relative velocity is the velocity of any point with respect to any other some point on the
same link.
V be the relative velocity of one end w.r.t. other end of link in m/sec
ω be the angular motion in rad/sec &
r as the length of same link in meter
Then, the relation is expressed as;
V = r x ω m/sec

List different types of ‘kinematic pair’.

Types of Kinematic pairs:
[1] According to the type of relative motion between the elements:
(a) Sliding pair.
(b) Turning pair.
(c) Rolling pair.
(d) Screw pair.
(e) Spherical pair.

[2] According to the type of contact between the elements:
(a) Lower pair.
(b) Higher pair.
[3] According to the type of closure:
(a) Self closed pair.
(b) Force - closed pair.
[4] According to Constrained Motion:
(a) Incompletely Constrained
(b) Completely Constrained
(c) Successfully Constrained

Define term ‘kinetics’

Definition of Kinetics:
It is that branch of Theory of Machines which deals with the inertia forces which arise from
the combined effect of the mass and motion of the machine parts.


stress is load per unit area.


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