In the brake system shown below, the clockwise couple Mc is applied to the brake drum C. (i) Determine the largest force exerted by the hydraulic cylinder on brake arm AB for which the brake drum will rotate if Mc is 300 Nm a. clockwise b. counterclockwise. The coefficient of static friction between the drum and arm is 0.50. (ii) If the coefficient of kinetic friction between the drum and arm is 0.40 and the hydraulic cylinder pushes end B to the left with a force of 1 kN, determine the friction force acting on the drum when the couple Mc is 300 Nm a. clockwise b. counterclockwise.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.