Why Is Answer A Correct for the Oscillation Problem?

[magiclink]

Homework Statement

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.

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!

 

[gneill]

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.

 

[Vipho]

Hi, magiclink!
Is that IB Physics?

 

[magiclink]

Hey! I just looked at the question and gave it a good look again. Turns out that the vectors did add vectorally to equal zero. A bit of an optical illusion to me. Thanks anyways! Sorry for wasting your time! :)


And yes, tis IB physics indeed. ;)

 

[asteriatic]

Hello,

It seems like you are having trouble understanding the concept of oscillation and how it applies to this particular problem. Oscillation refers to a repeated back-and-forth movement around an equilibrium point. In this case, the ball is held stationary at position P, which means it is at the equilibrium point. The forces acting on the ball are balanced, and the ball is not moving. If the ball were to be released, it would start oscillating around position P.

The question asks which force would cause the ball to return to position P if it is displaced. Since the ball is already at position P, the correct answer is A, as it represents the force that would bring the ball back to its equilibrium point. Option C refers to a force that would cause the ball to move away from its equilibrium point, which is not what is being asked in the question.

I hope this explanation helps clarify things for you. If you have any further questions, please don't hesitate to ask. Good luck with your homework!