Question

2.1.4 quiz: conservation of energy
question 8 of 10
a swimming pool is an example of an open system. the pool loses 10,500 j of its thermal energy to the surrounding air at night, and the surrounding air adds 2,500 j of thermal energy to the pool in the morning. according to the law of conservation of energy, what is the total change in energy?
a. a decrease of 8,000 j
b. a decrease of 13,000 j
c. an increase of 10,500 j
d. an increase of 2,500 j

Explanation:

Step1: Define energy changes

Losing energy is negative, gaining is positive. So loss: $-10500$ J, gain: $+2500$ J.

Step2: Calculate total change

Total change = $-10500 + 2500 = -8000$ J. Negative means decrease.

Answer:

A. A decrease of 8,000 J