If a heat engine pulls 4390.0 j of heat from the hot reservoir and exhausts 3582.2 j of heat to the cold reservoir, what was the work done by the engine? what is the efficiency of this engine in percent? (do not enter the percent sign)

18.4

Explanation:

Q1 = 4390 J

Q2 = 3582.2 J

The efficiency of heat engine is given by

n = 1 - Q2 / Q1

n = 1 - 3582.2 / 4390

n = 0.184

n = 18.4 %

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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