404) The gears are termed as medium velocity gears, if their peripheral velocity is

405) The product of the diametral pitch and circular pitch is equal to

406) If T₁ and T₂ are the tensions on the tight and slack sides of the belt respectively, and T_c is the centrifugal tension, then initial tension in the belt is equal to

407) The smallest diameter of an external or internal screw thread is known as

408) The process which improves the machinability of steels, but lowers the hardness and tensile strength is