80) The rocker arms in internal combustion engines are of first type levers.

81) In a crossed belt drive, the shafts are arranged parallel and rotate in the same directions.

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.