A rightward force of 30.0 N is applied to a 5.0-kg object to accelerate it across a horizontal surface. The object encounters 20.0 N of friction. What is the object's acceleration?
Select one:
O a. 10.0 m/s/s
O b. 4.0 m/s/s
O c. 2.0 m/s/s
O d. 6.0 m/s/s
O e None of these are correct.

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.

Ibelieve the answer is d. macula  hope my answer has you : )

Answer///(d) atoms contain small,negatively charged particles;