An object with charge 4.3 x 10-5 C pushes another object 3.1 x 10-7 m away with a force of 7 N. What is the total charge of the second object?

I believe you need to know the distance between the two charges in order to answer this question.

The best description is: . nobody has any idea what q is.

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.