35) A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaped mode, it has a frequency of vibration of 1

36) The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (?) is equal to

37) The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the

38) A pair of friction discs is an example of rolling pair.

39) In order to balance the reciprocating masses,