1.a. Explain how assumptions made in Lewis equation are taken into account during design?

1.b. Explain how the following factors influence the life of a bearing

i Load

ii Speed

iii Temperature

1.c. What are the advantages and disadvantages of V-belt drive over flat belt drive>

1.d. Why is it necessary to dissipate the heat generated when clutches operate?

1.e. Define the following terms used in worm gearing

i Lead

ii Lead angle

iii Normal pitch

iv Helix angle

2 Design a two stage spur gear reduction unit with 20$^\circ$ F. D involute teeth. The input shaft is connected to 9.5KW, 1400 rpm motor through a flexible coupling. The output shaft speed shall be approximately 200 rpm. The gears are made up of plain carbon steel . Find dynamic load and check for wear load. Decide the constructional details of the gear and pinon showing neat sketch.

3.a. Design a hydrodynamic bearing for a centrifugal pump to support a load of 8 KN when operating at 1600 rpm. Write assumption if required and analyze the performance.

3.b. A multiple disc clutch, steel on bronze, is to transmit 8 KW at 800 rpm . The inner radius of the contact is 40 mm and outer radius of the contact is 70 mm . The clutch operates is 0.5 N/mm². Use uniform wear theory.

1. The total number of steel and bronze discs
2. The actual axial force required
3. The actual average pressure
4. the actual maximum pressure

4.a. A rotary disc cam and central translator follower has following motion:- Forward stroke = 22 mm in 100$^\circ$ rotation of cam with SHM, dwell to complete the cycle.

Return stoke = 22 mm with SHM in 100$^\circ$ of cam rotation remaining dwell to complete.

Mass of follower is 1 Kg and cam shaft rotates at 500 rpm and maximum pressure angle is 25$^\circ$ during forward stroke. the external force is 310N during forward stroke and 55N during return stroke. Determine

1. Base circle radius
2. Design the cam
3. Design the spring
4. Calculate maximum cam shaft torque

5 A pair of bevel gear is required to transmit 8 KW power from a pinion shaft rotating at 400 rpm with reduction ratio 3.5. The shaft angle is 90$^\circ$ and drive is subjected to moderate shock and operates at 12 hrs/day.

Design stresses for pinion are 380 MPa and 1100 MPa. Design and check pair in strength and wear and also perform arm design.

6.a. A V-belt drive is to transmit 15KW to a compressor. The motor speed is 1100 rpm an compressor pulley runs at 400 rpm. The coefficient of friction between the belt and pulley is 0.25. the compressor operates for 10-12 hrs/day . Design the drive for above application. Design should include following:

1. Section of V-Belt material
2. Exact center distance
3. Belt size
4. Number of belts
5. Life of belt

6.b. An angular contract ball bearing issued for gear shaft to support a radial load of 9 KN and 6 KN along the axial direction. The shaft rotates at 50 rpm. Select suitable size of bearing, if it is required to have a life of 30000 hrs with a probability of survival of 93%. Check selected bearing is safe for given application.