Question

The total mechanical energy of a system as a function of time is shown in the graph. Which of the following statements is true regarding the system?
A
The system should be classified as a closed system because the total mechanical energy lost from t = 3 s tot = 5s was gained from
t = 6 s to t = 9 s.
B
The system should be classified as an open system because mechanical energy can be added and removed from the system.
с
The system should be classified as an open system because the curve in the graph is symmetrical.
D
The system should be classified as a closed system because the system's total mechanical energy does not change from t = 0s to t = 10 s.

Answer 1

Answer: B

Explanation: A system is a closed system only if mechanical energy is constant. Because the graph showed the mechanical energy decreased before increasing again, it is not constant, even though the energy is equal at the end of the graph.