comes from the hot-water heater.2 points. 1 point for correct setup. 1 point for correct answer with
calculations. Alternative setups are acceptable. If your answer in part (b) is
incorrect but you appropriately used information from part (a) as the basis for
answering the question, you will receive full credit, even if the numerical
answer is wrong.18,720 gallons/2 = 9,360 gallons of hot water per yearLaws of Thermodynamics
FIRST LAW
Energy cannot be created or destroyed.
SECOND LAW
When energy is converted from one form to another, a less useful form results
(energy quality). Energy cannot be recycled to a higher quality. Only 20% of the
energy in gasoline is converted to mechanical energy while the rest is lost as heat
and is known as low-quality energy.
ENERGY CONSUMPTION (PAST)
Wood (a renewable energy source) served as the primary form of energy until
the mid- to late-1800s, even though water mills were important to some early
industrial growth. Coal became dominant in the late 19th century before being
overtaken by oil in the middle of the 20th century, a time when natural gas usage
also rose quickly. From the late 19th century until the early 21st century, coal
and oil were the world’s primary sources of energy with the largest growth.