Afire helicopter carries a 706 kg bucket at the end of a 8.6 m long cable. when the helicopter is returning from a fire at a constant speed of 28.4 m/s, the cable makes an angle of 33.6 ◦ with respect to the vertical. determine the force exerted by air resistence on the bucket.

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.