46) In a flange coupling, the thickness of flanges is taken as one-half the diameter of shaft.

47) The rolling contact bearings are known as

48) The backlash for spur gears depends upon

49) The size of a gear is usually specified by

50) The circumferential and longitudinal strains in a cylindrical boiler under internal steam pressure are ?_c and ?_l respectively. The change in volume of the boiler cylinder per unit volume will be