# Homework Help: Oscillation problem, help!

1. Apr 10, 2012

1. The problem statement, all variables and given/known data
Hi! My question is about oscillation. The multiple choice answers and question is included in the picture attached! I also happen to know the answer is A by looking at the marscheme.

3. The attempt at a solution
I would've thought that since the ball is said to be held "stationary" in that position the forces would all have to be equal. Thus i would've thought C was the correct answer. If they had said that it's an oscillation where the ball is in position P and not mentioned it being held stationary, I would've answered A, however, knowing that the forces would've had to be unbalanced and acting towards the equilbrium point. Could anybody explain exactly why it's A? and not C? I think my problem is probably largely due to interpretation of the question. Thankyou for any replies!

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• ###### Oscillation question.jpg
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2. Apr 10, 2012

### Staff: Mentor

If the ball is stationary then the forces must sum to zero net force. If they were all equal, would the sum be zero? Remember, you're adding vectors here.

3. Apr 10, 2012