x Turn on thread page Beta
 You are Here: Home >< Physics

# AQA Physics PHYA4 - 20th June 2016 [Exam Discussion Thread] watch

1. (Original post by Yo12345)
Amplitude must be small

Posted from TSR Mobile
I said the angle between the equilibrium position of the string at rest and the the position of the line at the amplitude must be 10 degrees when I measured out when to drop the ball. Sounds acceptable?
2. (Original post by ombtom)
Instead of using v and V I'll use v = 2, V = -1 for the velocities.

Everyone's saying mv - VN = 0
So V = mv/N
-1 = 2m/N

Since m/N > 0, this implies that -1 = 2 x positive constant.

What's going on?
If V=-1 the formula would be mv+VN=0. However, considering right to be positive mv-VN=0 is the correct momentum conservation.
3. To be honest it will probably end up with them accepting both positive and negative due to all the confusion.
4. How many marks was the radius calculation? Was it worth 2 or 3?
5. (Original post by marioman)
If only... I think more like 57 for an A* if we're lucky. 62 or 63 for 120 UMS depending on standard deviation.

And I think that's me being conservative.
Ok i got scared for a moment xD, I didn't do well on this paper :/ couldnt even answer the time constant question... and the kinetic energy fml
Yeah the E_alpha derivation got me too. I only managed to get to something like:

E_alpha = E(1 - ((1/2N)m^2v^2)/E)

7. Does anyone have an unofficial markscheme?
8. (Original post by English-help)
Thanks you! I need 85+ in Unit 5 now which will be hard but i'll have to get it for my offer! :/
Best of luck to you! What is your offer for, which grades and where?
9. All these multiple choice answers with many D's, I don't really think its right. I barely had D's...
Defo 2F and X to Y.
if they are both positive, then the force on X has direction Y to X (repulsive).
11. (Original post by js.int)
Yeah the E_alpha derivation got me too. I only managed to get to something like:

E_alpha = E(1 - ((1/2N)m^2v^2)/E)

Yeah, that was the one question where I just couldn't see how to get to it.

Everything else was either a case of "Oh I know this" or "Ahhh I wish I revised this more" but.. this one.. I just couldn't recall anything about it at all and I couldn't derive the right equation
12. What was the momentum of the alpha particle ? 8.6x10^-19???
13. (Original post by Sid1234)
if they are both positive, then the force on X has direction Y to X (repulsive).
Initially it was negative and was y to x. after, the potential was positive, so must have changed direction .
14. (Original post by Tokhmehsag)
What was the momentum of the alpha particle ? 8.6x10^-19???

I got like 2*10^-20
All these multiple choice answers with many D's, I don't really think its right. I barely had D's...
Just so you know, for the past 10 past papers, there has always been an even distribution of answers A, B, C and D. In every paper so far, there's been 6 answers for 3 letters and then 7 answers for 1 letter.
16. (Original post by Tokhmehsag)
What was the momentum of the alpha particle ? 8.6x10^-19???
I got 1.6*19^-19 or something like that
17. (Original post by Sid1234)
if they are both positive, then the force on X has direction Y to X (repulsive).
Yeah agree
18. (Original post by tanyapotter)
How many marks was the radius calculation? Was it worth 2 or 3?
The radius of Venus question was worth 3 marks
19. (Original post by Tokhmehsag)
What was the momentum of the alpha particle ? 8.6x10^-19???
Nope, missed factor at the end (I got this and corrected)
20. (Original post by Random1357)
Nope, missed factor at the end (I got this and corrected)
What did you end up getting? A fair few in my college on one or two said 1.15x10^-19 (I think it was ^-19 anyway)

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 9, 2017
Today on TSR

### Unconditional offer...

But going to get a U!

### I work at the House of Commons, AMA!

Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE