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# Edexcel AS/A2 Mathematics M1 - 8th June 2016 - Official Thread watch

1. I can find the moments for the others but i don't know what to do with X. i worked out that its length is 2root2 but then how do i find its moment, multiply by 2 to get the distance of X from D? i.e. my question is how to get the moment of X?
2. (Original post by AlvlVictim)
You have to draw a diagram and stuff its complex check mark scheme
I've checked the mark scheme and I can't really make sense of it.

3. For resolving forces questions is it ok to annotate the diagram? Or do you have to draw a new one out? Basically will you lose marks if you do your working on the diagram given?

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4. do you think i can teach myself this unit and still revise for psychology unit 3 in 6 hours?? lmao help me
5. I saw a couple pages back someone said that if there is a part (i) and (ii) you lose marks if you do it in the wrong order...I'm 95% sure that's wrong, why would you be penalised anyway? You've still shown that you can do it?

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6. (Original post by NickLCFC)
I've checked the mark scheme and I can't really make sense of it.

(Massive diagram ting)
Someone on the interwebs explained it in a way which makes more sense, IMO:

The pipeline runs north-south, going through point (6i, 0j + 0k). You can therefore create a vector equation out of this by doing
r = (6i + 0j + 0k) + x(0i + 1j + 0k) (velocity is 0i + 1j + 0k because the pipeline is running in the j unit direction basically).

Then you can create a second equation using the position of the mast, which goes through the point (0i + 2j + 0k). The "velocity" would be (-1i + -1j + 0k) because the radio mast is south-west to the walker (if you think about going one unit to the left and one down, the direction would be south west).

So you get r = (0i + 2j + 0k) + y(-1i -1j + 0k)

you then set these two equations equal to each other to find where the walker is, work out a value for x or y and sub it into the respective equation (you should get the same answer in either case) to get (6i + 8j)!
7. (Original post by NickLCFC)

Can someone explain how the answer to part a) is (6i + 8j)?
6i is pretty self explanatory from the question.
8j however requires trig. Draw a diagram, and we know that south west is 45 in a downwards left direction. Use trigonometry on the triangle (using 6i) namely the tan function. Then add the 2j. This explanation becomes clear with a diagram.
8. Sorry.. i suck at paint

(Original post by NickLCFC)
I've checked the mark scheme and I can't really make sense of it.
6i is pretty self explanatory from the question.
8j however requires trig. Draw a diagram, and we know that south west is 45 in a downwards left direction. Use trigonometry on the triangle (using 6i) namely the tan function. Then add the 2j. This explanation becomes clear with a diagram.
Okay that makes so much more sense hahaha
Sorry.. i suck at paint
Thanks mate
11. (Original post by Don Joiner)
I saw a couple pages back someone said that if there is a part (i) and (ii) you lose marks if you do it in the wrong order...I'm 95% sure that's wrong, why would you be penalised anyway? You've still shown that you can do it?

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You wouldn't be penalised. I personally do not label my questions. The marker must mark everything legible on your paper.
12. (Original post by n2697)
I can find the moments for the others but i don't know what to do with X. i worked out that its length is 2root2 but then how do i find its moment, multiply by 2 to get the distance of X from D? i.e. my question is how to get the moment of X?
Didn't think moments with non-perpendicular angles was in M1 but anyway, I guess we need to take moments about D
So (5 x 2) + (3 x 2) = Xcos45 x 2
(this is using force x perp distance)
So 10 + 6 = 2X x rt2/2
16 = X x rt2
16 rt 2 = 2X
so X = 8 rt 2 I guess
13. GUYS ANY LAST TIPS BEFORE THE EXAM?

BTW GOOD LUCK! HOPE EVERYONE DOES GOOD
14. (Original post by wenogk)
GUYS ANY LAST TIPS BEFORE THE EXAM?

BTW GOOD LUCK! HOPE EVERYONE DOES GOOD
Check if the question says:

speed or velocity
mass or weight
acceleration or decceleration

dont skip steps in long complex calculations, do one step at a time so when you are checking answers you can spot any errors more clearly

good luck to you too!
15. Does anyone know how to use the information when something is north west or south west etc in a vectors question? I know it's 45 degrees but idk how that helps.
I can do it when it's north or south or east or west as I know the i/j components are the same. But when it's like north west or something it confuses me
Example question:
16. Does this clash with FP2 again? Was a fun clash for me last year
17. (Original post by jtlmao)
For resolving forces questions is it ok to annotate the diagram? Or do you have to draw a new one out? Basically will you lose marks if you do your working on the diagram given?

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No you won't loose marks
18. (Original post by Tim73)
Does anyone know how to use the information when something is north west or south west etc in a vectors question? I know it's 45 degrees but idk how that helps.
I can do it when it's north or south or east or west as I know the i/j components are the same. But when it's like north west or something it confuses me
Example question:
When Q is north west of P, the J component will stay the same, but you have to use the negative of the I component from the equation for PQ as it would be on the left. Then equate them.
19. (Original post by Tim73)
Does anyone know how to use the information when something is north west or south west etc in a vectors question? I know it's 45 degrees but idk how that helps.
I can do it when it's north or south or east or west as I know the i/j components are the same. But when it's like north west or something it confuses me
Example question:
In this question you can use vector PQ from part b to help you. This vector must equate to k(-I + j) where k is just a constant.
Now equate the i's and the j's to equal -k and k respectively.
Then combine equations and solve for t
20. (Original post by candol)
Didn't think moments with non-perpendicular angles was in M1 but anyway, I guess we need to take moments about D
So (5 x 2) + (3 x 2) = Xcos45 x 2
(this is using force x perp distance)
So 10 + 6 = 2X x rt2/2
16 = X x rt2
16 rt 2 = 2X
so X = 8 rt 2 I guess
i gt da same answer too fr k

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