At the start of the compression stroke of a diesel cycle, the air pressure and temperature are 100 kpa, 27 °c. this diesel engine has a compression ratio of 20 and a cutoff ratio of 1.5. answer the following questions using cold-air standard analysis assumptions. a)-what is the temperature of the air at the start of the combustion (heat addition) process? a. 415 °c b. 523 oc c. 721 °c d. 805 °c
b)-what is the maximum cycle temperature? a. 1292 °c b. 1391 °c c. 1491 °c d. 1550 °c. c)-what is the thermal efficiency of this engine? a. 0.664 b. 0.670 c. 0.676 d. 0.684 d)-how much work is produced during the combustion (heat addition) process? a. 85.5 kj/kg b. 114 kj/kg c. 143 kj/kg d. 289 kj/kg. e)-what is the rate at which heat must be added to this engine if it is to produce 1 mw of power? a. 1.40 mw b. 1.46 mw c. 1.47 mw d. 1.49 mw

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.