60) When a nut is tightened by placing a washer below it, the bolt will be subjected to

61) A locking device extensively used in marine type connecting rod ends is a

62) The difference between the tooth space and the tooth thickness as measured on the pitch circle, is called

63) When a load W is suddenly applied to a bar of weight W₁, the stress induced in the bar will increase with the increase in weight W₁.

64) The endurance limit for a mirror polished material will be __________ as compared to unpolished material.