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This question pertains to the pendulum system of passage II.
Here is the answer explanation as to why D is correct.
Choices A and C can be eliminated immediately, because both of them depict systems in which only one of the two balls is displaced.
I get this since W=∆E. In this case ∆E=m*g*∆h, but m represents total mass.
In choice B (System I), the center of mass when the system is at rest is lower than for choice D (System II), so that point is displaced by a greater distance when System I is moved by the same angular amount as System II. The greater the displacement of the center of mass, the greater the change in the potential energy of the system.
This portion of the explanation confuses me in two ways: (i) because in Choice B, I thought the center of mass was HIGHER since the larger of the two masses is higher and (ii) they called Choice B (System I) but from the passage, this choice would represent System II.
Is there a mislabeling in the answer choices?
Here is the answer explanation as to why D is correct.
Choices A and C can be eliminated immediately, because both of them depict systems in which only one of the two balls is displaced.
I get this since W=∆E. In this case ∆E=m*g*∆h, but m represents total mass.
In choice B (System I), the center of mass when the system is at rest is lower than for choice D (System II), so that point is displaced by a greater distance when System I is moved by the same angular amount as System II. The greater the displacement of the center of mass, the greater the change in the potential energy of the system.
This portion of the explanation confuses me in two ways: (i) because in Choice B, I thought the center of mass was HIGHER since the larger of the two masses is higher and (ii) they called Choice B (System I) but from the passage, this choice would represent System II.
Is there a mislabeling in the answer choices?
