AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread]

Damping affects amplitude, not time period. Time period is irrelevant.
Conservation of momentum means that the ringed bob experiences less damping because it has higher mass so gives the air molecules less velocity (assuming the same surface area).

Yes if horizontal Tsin(x)=mg , though in practicality its unrealistic to apply this tension apparently. I didn't even mention anything to do with this though, so probably only got 4-5/6

No you were correct the first time in saying there is the same amount of drag. Force is the same as rate of change of momentum of u can remember q1 on multiple choice. This means the same amount of drag will have the same rate of change of momentum. Since velocity is independent of mass the initial velocity is the same, as is the time period. But since the mass is larger and the rate of change of momentum is equal to before means that the rate of change of velocity is reduced meaning it takes longer to lose its velocity hence less damping

Preach 🙌🏻

Just heard back from my school who called AQA; they have realised that its a mistake!!

Just heard back from my school who called AQA; they have realised that its a mistake!!

Did you get any information how they're going to account for it by any chance?

what typo?

Does anyone have a copy of the paper?

Cool, hopefully they won't penalize for not including exactly that as I don't think we even had to talk "quantitatively" anywhere in the question. (6-markers are qualitative assessments)

I do remember saying that the weight of the ball is much less than the centripetal force though (but I didn't justify this with a calculation)

I agree, i see my mistake. I concluded that the drag force is the same, but I forgot what it was opposing (the momentum of the bob). So the drag force is NOT the damping force? I always thought this was the case with pendulums.

Yooooooo was the first answer weight??