82) In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as

83) Idler pulley is used for

84) The bell crank levers used in railway signalling arrangement are of third type levers.

85) When spring index increases, the value of Wahl's stress factor

86) A shaft is subjected to a maximum bending stress of 80 N/mm² and maximum shearing stress equal to 30 N/mm² at a particular section. If the yield point in tension of the material is 280 N/mm² and the maximum shear stress the