A moon of mass 1 x 1020 kg is in a circular orbit around a planet. The planet exerts a gravitational force of 2 x 1021 N on the moon. The centripetal acceleration of the moon is most nearly

This is the answer: body 1 + engine 2

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.

All are great precautions but you can still lift lighter and different muscles in between hard workdays. this keeps other muscles not usually used in shape.