Two cars start moving from the same point. One travels south at 64 mi/h and the other travels west at 48 mi/h. At what rate (in mi/h) is the distance between the cars increasing three hours later? g

If the heat engine is a perfect carnot cycle engine, thenefficiency = (t2-t1)/t2   where t1=temperature of cold reservoir ( ° k) = 135            t2=temperature of hot reservoir ( ° k)   = 325thereforeefficiency = (t2-t1)/t2 = (325-135)/325 = 0.5846 = 58%  note: this is the theoretical maximum efficiency of a perfect heat engine.   real-life engines do not achieve this value.

In the conservation of mass, mass (which is the same as energy) can never be created or destroyed in the same way oil is formed from the remains of small animals and plants that died and fell to the bottom of the sea and their mass (energy) is conserved as oil.