A father and son own a flooring company. When working togeth…

A father and son own a flooring company. When working together they can refinish a floor in 5 hours. However, when the son is working by himself, it takes him 24 hours longer than his father to complete a job. How long would it take the father to finish refinishing the flooring on his own without his son’s help? How long does the son take working on his own?  The father takes  hours working by himself, while his son takes hours working alone. 

A heat engine takes in 400 J of energy from a hot reservoir…

A heat engine takes in 400 J of energy from a hot reservoir and performs 16.0 J of work in each cycle. (a) Find the efficiency of the engine. (10 points) (b) Find the energy expelled to the cold reservoir in each cycle. (15 points) Show your work and answer in the scratch paper.

Metal lids on glass jars often become easier to loosen when…

Metal lids on glass jars often become easier to loosen when hot water is run over them. Explain the physical principles behind this phenomenon, including the differences in material properties between the lid and the jar.  The coefficient of thermal expansion of glass is 3.2×10−6/◦C and the coefficient of thermal expansion of aluminum is 25 × 10−6/◦C. Record your answer with your reasoning to your scratch paper. Make sure to submit it to Gradescope at the end of the exam. (10 points)