Two mating spur gear with module pitch of 6.5 mm have 19 and 47 teeth of 20 degree pressure angle, and 6.5 mm addendum. Evaluate the number of pairs of teeth in contact and the angle turned through by the larger wheel for one pair of teeth in contact. Evaluate also the sliding velocity at the instant (a) Engagement condition (b) pitch point (c) Dis-engagement condition. When the pitch line velocity is 1.2 m/sec.