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.
OR
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
driver pulley. This is known as Slip of the belt & generally expressed in %
Slip of Belt by neglecting thickness of belt is expressed as below;

Creep: When the belt passes from the slack side to the tight side, a certain portion of
the belt extends and it contracts again when the belt passes from the tight side to
slack side. Due to these changes of length, there is a relative motion between the belt
and the pulley surfaces. This relative motion is termed as creep.
Creep reduces velocity ratio and also power transmission capacity of the belt drive.
Less creep in the belt drive is desirable.
Creep of Belt is expressed as below;