What force (size and direction) must exert the hand of a ball-thrower on the ball with m = 7,25 kg, so that it accelerates evenly on a 1,7 m long 42 ° rising distance, so that after leaving the hand in 2 m above the ground and 0.5 m before the start of the test, a throw of 18 m? calculate with g = 10 m / s2.

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.