What is the mass of a solid iron wrecking ball with a radius of 0.18 m?

Answerapplying a direct current to a non magnetic material in order to create a electromagnetic field; plz check first good luck;

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.

  the answer is don't know.