2007 hsc q.15 (1 Viewer)

[FlyingGullible]

http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/physics-07.pdf
Hi guys, I was just wondering for MC q.15 of this paper.
I get how B, C and D can all be done through conservation of energy. But for A, couldn't you also use conservation of energy to say, launch a particle of known mass and velocity at the proton and use conservation laws to calculate back from there? I thought that was how neutrons and other particles' properties were discovered in the first place (though I think they were moving in those cases, but I can't see why that makes a difference).

 

[Kaido]

No, you're overthinking lol
Just substitute the known mass of a proton and you can calculate the mass.

 

[mrpotatoed]

I think its trying to test you to see if you know that E=mc^2 is not the conservation of energy but rather mass-energy equivalence

 

[sy37]

http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/physics-07.pdf
Hi guys, I was just wondering for MC q.15 of this paper.
I get how B, C and D can all be done through conservation of energy. But for A, couldn't you also use conservation of energy to say, launch a particle of known mass and velocity at the proton and use conservation laws to calculate back from there? I thought that was how neutrons and other particles' properties were discovered in the first place (though I think they were moving in those cases, but I can't see why that makes a difference).

I see what you are saying, but the question says of a proton at rest.

For questions as is this I'd work through it by way of elimination (which is much easier imo, as you did)