Aplayground merry-go-round with a radius of 1.80 m has a mass of 120 kg and is rotating with an angular speed of 0.400 rev/s. what is its angular speed after a 37.5-kg child gets onto it by grabbing its outer edge? the child is initially at rest.

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.