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# EDEXCEL A2 Physics EXAM Unit 4 Physics On The Move 20th June 2016 (NOT I-A-L)

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1. (Original post by josephinemar25)
I put +1-1+1-1 as there was the hydrogen ion, ejected electron and electron-positron pair?? Not sure what Did others get
Got this ^
(+1-1+1-1)
2. (Original post by josephinemar25)
I put +1-1+1-1 as there was the hydrogen ion, ejected electron and electron-positron pair?? Not sure what Did others get
Charge of photon = 0 , Charge of Atom = 0
Charge of positron = +1, Charge of electrons = - 1 * 2 , charge of ion = +1 so total = zero
3. (Original post by josephinemar25)
I put +1-1+1-1 as there was the hydrogen ion, ejected electron and electron-positron pair?? Not sure what Did others get
I think that is correct but i didnt do that just mentioned electron positron
4. Has someone set up a poll. So we could get a better idea or what the boundaries might be like?
5. (Original post by josephinemar25)
I put +1-1+1-1 as there was the hydrogen ion, ejected electron and electron-positron pair?? Not sure what Did others get
Same, +1-1+1-1.
6. (Original post by callum9977)
Got this ^
(+1-1+1-1)
It was a neutral hydrogen wasn't it?
7. (Original post by KINGYusuf)
It was a neutral hydrogen wasn't it?
It was to start with then ejected an electron
8. (Original post by KINGYusuf)
It was a neutral hydrogen wasn't it?
Neutral at start, became +1 after once electron removed
9. (Original post by 12amadaeus)
The question asked for the maximum percentage decrease so wouldn't you use the maximum change in distance?
I thought that at first, then I thought if you're at 35mm then the max increase is 17% and the max decrease is 17%, so you can go up or down. The wording of the question was confusing, but I'm fairly sure 17% was the right answer, because you're looking at max decrease not max change
10. Yep, I got exactly the same.

(Original post by lilywatts16)
I got 67% i think!
11. What did people put for why it wasn't deflected as much, effect of flat tire, need for low friction and graph question? Grade boundaries?
12. Can someone explain how they got the radius of the bike?

I thought I did it correctly but got around 9m 😭
13. (Original post by target21859)
What did people put for why it wasn't deflected as much, effect of flat tire, need for low friction and graph question? Grade boundaries?
I put the velocity was greater for the high speed electron, and r=mv/BQ so its path would have a greater radius i.e. it would be less deflected

Struggled with the friction one, I put so that no momentum was transferred to the track and the system remained 'closed'...? Also struggled with that 5 marker with light gates and gliders, what did other people get for that?

For the flat tire, the radius would decrease, and the speed on the speedo is inversely proportional to radius so the speedo would display a higher speed than the true value
14. (Original post by target21859)
What did people put for why it wasn't deflected as much, effect of flat tire, need for low friction and graph question? Grade boundaries?
My answers were so random lol:

Deflection - less work done or something and less acceleration

Low-friction - so no/little external force acts as this is a necessary requirement for the conservation of momentum. I also talked about so that the kinetic energy isn't all transferred to thermal energy due to friction, and that so that the velocity doesn't decrease as much

(basically random bs)

graph I drew the curve then extended it into a horizontal line

I said the graph will become completely horizontal at a value under the speed of light (3x10^8 m/s) so it will never go above the speed of light. Probably wrote alil more random
15. (Original post by target21859)
What did people put for why it wasn't deflected as much, effect of flat tire, need for low friction and graph question? Grade boundaries?
Wasn't deflected as much because it has higher momentum and faster speed, effect of flat tire I said the value would be exaggerated, i.e. higher than the actual value, but wouldn't change as angular velocity is constant. Need for low friction because conservation of momentum only holds when no external forces are applied and also that the velocity at timer would be less than velocity at collision due to friction.
For the graph question, were we required to draw the graph? Were there any marks for that ?
16. What speed was the bike travelling at in the question, I'm pretty sure I used 6ms^-1
17. (Original post by KINGYusuf)
My answers were so random lol:

Deflection - less work done or something and less acceleration

Low-friction - so no/little external force acts as this is a necessary requirement for the conservation of momentum. I also talked about so that the kinetic energy isn't all transferred to thermal energy due to friction, and that so that the velocity doesn't decrease as much

(basically random bs)

graph I drew the curve then extended it into a horizontal line

I said the graph will become completely horizontal at a value under the speed of light (3x10^8 m/s) so it will never go above the speed of light. Probably wrote alil more random
Did we have to draw the graph?
18. (Original post by Pinocchiolewis)
Can someone explain how they got the radius of the bike?

I thought I did it correctly but got around 9m 😭
Resolve vertically: F*sin22 = 80 * 9.81 gives F = 846

Set horizontal component equal to mv^2/r, rearrange to get

r = (80 * 9^2) / (846 * cos22) which gives you 20.4m
19. (Original post by oShahpo)
Did we have to draw the graph?
I did just incase as it said "use the graph"
20. (Original post by jtebbbs)
I thought that at first, then I thought if you're at 35mm then the max increase is 17% and the max decrease is 17%, so you can go up or down. The wording of the question was confusing, but I'm fairly sure 17% was the right answer, because you're looking at max decrease not max change
Thank you!!!!!!!!! I insisted on 33.3% until I saw your comment. 👍

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