15. Sandra decided to talk a walk at her neighborhood park. She walks 20 meters east, 40 meters west, and finally 50 meters east. What is her total distance
and displacement, respectively?

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.

Answer(b) both involve the use of levers;

This question is incomplete and not physics but i'm  willing to if you can give a better question