- #1

LCSphysicist

- 646

- 162

- Homework Statement
- All below

- Relevant Equations
- There is no.

The question is:

We have a system with two pendulum attached to a spring, both pendulum are connected in the ceiling by strings. The strings, and the bobs are equal.

So now you pick the bob A and pull it to an initial displacement, maintaining the second bob in rest. Now, you let the first go. So the initial conditions are:

Xo(A) = Xa

Xo(B) = Vo(A) = Vo(B) = 0

You see the system made one oscillation, and you now go out the room.

After a time, you returned in the exact moment the pendulums have the same energy, the same displacement and so.

The time stop, the question is: How would you know which pendulum will lose energy, which will gain or if the energy of both pendulums will not change.

I am not sure if i get the question...

At first i would say it is impossible to give a answer, we can not distinguish. But i think if we know the phases in this instant, we can give and answer, so my answer would be:

"If we know, by some reason, what are the phase in this instant, we can give an answer (with phase i want to say: if we know the pendulum A is, let's say, one quarter of period after the start). Otherwise, it is not possible"

What do you think?