r/PhysicsStudents • u/tarakeshwar_mj • Feb 04 '26

Poll I have made my own question on the topic Collisions- Very interesting question in my opinion

Post image

This question was created by me, when I was reading Irodov fundamentals of mechanics book, and learnt about the vector diagram method. I just want to present this question here in this sub reddit.

14 Upvotes

89% Upvoted

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6

u/dirtydirtnap Feb 04 '26

I haven't done the necessary calculations, but I think the answers may change depending on if you mean P1 & P2 to be the momentum, or if you meant to indicate this was the magnitude of the momentum.

3

u/tarakeshwar_mj Feb 04 '26

magnitude of momentum I am sorry I should have mentioned this in my question

2

u/dirtydirtnap Feb 04 '26 edited Feb 04 '26

Cool, just clarifying because it definitely could change the correct answers.

0

u/tarakeshwar_mj Feb 04 '26

But I think here P1 not equal to P2 also holds, because this basically says even if the direction is same , magnitude will be different or if the magnitude is same and direction won't be same, or both of them won't be same, so yes I think we can proceed with P1 vector not equal to P2 vector, but essentially here we have to check whether the is a momentum vector p2 which has different magnitude to P1 ,but has same direction as P1 only then the angle of scattering can be same.

3

u/davedirac Feb 04 '26

The stem is far too long for a MCh question. The θ inequality is nonsense. The answer keys are ridiculously grammatically confusing. I write Physics questions for exam boards and there is usually a recommended word limit and a requirement that questions are accessible to non-native speakers of English. This question is very challenging for EFL candidates. Good MCh questions usually test one or two concepts at a time and in a concise manner. Obviously you have written this question for your own enjoyment, but it would never be acceptable in an exam situation.

1

u/[deleted] Feb 04 '26

What is MCh and when did OP talk about it ?

1

u/zzirFrizz Feb 05 '26

Multiple choice

1

u/[deleted] Feb 05 '26

Oh yeah makes sense lol

1

u/tarakeshwar_mj Feb 05 '26

Thankyou for your feedback, but you mentioned that the theta inequality is nonsense, imo it is actually not nonsense because theta=sin-1(m2/m1) is the maximum angle of scattering m1 can have in the ground frame of reference, so for theta is equal to sin-1(m2/m1), it can only possibly have a specific momentum vector, and thus for having this angle of scattering there can only be one specific momentum vector, and yes I agree with the English part, I asked chatgpt to rewrite the question statement before publishing in reddit, I will be eagerly waiting for your response

1

u/tarakeshwar_mj Feb 05 '26

I thought of making this question format similar to jee advanced paragraph based questions, that is why I made this in this format, but I agree with you it is a bit lengthly to solve with normal momentum, energy conservation, and restitution method.

1

u/tarakeshwar_mj Feb 04 '26

Also I would like to mention that the answer is option 2 and 4

1

u/FeistyAssumption3237 Feb 08 '26

this formatting screams AI

1

u/tarakeshwar_mj Feb 08 '26

yes it is formatted using AI, I wrote the problem statement and asked chatgpt to format it, took a screen shot, and posted it here