1. A single plate clutch, consisting of two pairs of contacting surfaces, is required to transmit 50kW power at 2500 rpm. The coefficient of friction between the contacting surface is 0.1 and the intensity of pressure is limited to $0.3 \mathrm{N} / \mathrm{mm}^{2}$. The outer diameter of the friction disk is limited to 400 mm.

If the service factor is 1.25, Determine,

• The inner diameter of friction disk.

• The axial force required to engage the clutch.

2. Multi-disk clutch, consisting of alternate steel & bronze plates, is used to transmit 7.5 Kw power at 720 rpm. The inner and outer diameters of contacting surface are 100 mm and 150 mm respectively. The coefficient of friction between the contacting surfaces is 0.12. If the intensity of pressure is limited to $0.3 \mathrm{N} / \mathrm{mm}^{2}$ ,

Determine:

• The number of steel and bronze plates and
• The axial force required to engage the clutch

3. A cone clutch is used to transmit 20 kW at 1200 rpm. The coefficient of friction of 0.2, while the permissible intensity of pressure is $0.25 \mathrm{N} / \mathrm{mm}^{2}$ .The semi cone angle is 15 degree, the larger diameter of the friction surface is 240 mm. if the overload factor is 1.25, Determine: The dimension of the clutch, Axial force required to engage and disengage the clutch.

4. A 80 kN four wheeler two axle full trailer is equipped with two short shoe brakes mounted on 1200mm diameter, two rear wheels. The load is equally shared by two axles. The trailer is brought to rest in a distance of 30m when running at 32kmph. Design brake drum, shoe and check for heat dissipation capacity assuming 20 braking operations per hour.

5. The block type hand brake shown in fig. has a face width of 45 mm. The friction material permits a maximum pressure of 0.6 MPa and a coefficient of friction of 0.24.

Determine;

• Effort F

• Maximum torque,

• Heat generated

if the speed of the drum is 100 rpm and the brake is applied for 5 sec. at full capacity to bring the shaft to stop.