4. A pair of meshing spur gears with pressure angles () of 20 and a module (m) of 2. The pinion has 20 teeth (72) and the gear has 40 teeth (73). Determine center distance (C) of the two gears. When the center distance is accidentally increased by 0.3 mm, determine the new pressure angle. 5. A pair of mating gears with velocity ratio (w,/w, -1/2) is selected in a gear train. The gear pressure angle is 20. The module is 8 and so is the addendum. The number of teeth of the input gear (T2) is 15. (A) Find the contact ratio. (B) Determine if interference will occur or not? 6. A manual transmission gear box is shown with the numbers of teeth of T, =15, 7, 21, T=26, T=30, T=24, T=19, T=13, and I=14. Determine the velocity ratio of the first gear, the second gear, the third gear (direct drive gear), and the reverse gear. 7. A planetary gear train is shown the numbers of teeth 32, 14, I=60. Determine the velocity of ratio when Clutch teeth- 1 To engine (1) Sun gear 2 serves as the input, Carrier 5 serves as the output, and Ring gear 4 is braked. (2) Sun gear 2 serves as the input, Ring gear 4 serves as the output. and Carrier 5 is braked. (3) Ring gear 4 serves as the input, Carrier 5 serves as the output, To wheels 15 Im 1 1 and Sun gear 2 is braked.