As a skateboarder moves downhill, some of the energy of the skateboarder is A)
lost.
B)
kinetic
09
potential
D)
kinetic and some is potential
TH:

The Answer is D) kinetic and some is potential

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.