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# OCR MEI Core 4 (C4 4754/01 and 4754/02) watch

1. Oh I've flopped that graph then...
What I did was I picked a midpoint for each interval and plotted a point for each, then drew a line... and for the second part I said it had a positive correlation(plus I also said as the annual passengers increase, so do the number of trains,etc.)
2. (Original post by Tallon)
B.
Was that 10cm?
3. (Original post by DeanT)
For the second part of that question is it just: n (number of trains per day) is directly proportional to p (number of passengers per year)?
I don't think that would be right, since it's implying that the number of trains per day increases linearly from zero as the number of annual passengers increases, where the graph started at n = 10 and went up by 1 after each additional 5 x 10^5 passengers.

For that question I wrote something like "as the number of trains increases by one, the number of annual passengers increases by 5 x 10^5 (from 10^6 onwards) whilst there are 10 trains minimum.

Would this be right?
4. (Original post by treemantris)
Was that 10cm?

yeah
5. (Original post by OL1V3R)
I don't think that would be right, since it's implying that the number of trains per day increases linearly from zero as the number of annual passengers increases, where the graph started at n = 10 and went up by 1 after each additional 5 x 10^5 passengers.

For that question I wrote something like "as the number of trains increases by one, the number of annual passengers increases by 5 x 10^5 (from 10^6 onwards) whilst there are 10 trains minimum.

Would this be right?

I think I put something like, "as n increases by one (from n = 10 onwards), the number of passangers increases from a range of 0 to 0.5*10^6"
6. (Original post by OL1V3R)
For Q5 on the comprehension I put to the nearest 10cm because that's as accurate as the number of significant figures can provide.

What did everyone do with the vectors question, where you had to calculate the angle of the pipeline with the vertical? I basically found the dot-product of the pipeline's direction vector with the unit vector in the z-direction and used the formula cosθ = a.b/|a||b| to calculate the angle it made with this unit vector. Would that be a reasonable method?
you had to use the vector of the pipeline against a vector of the vertical, say (0i+0j+z) and then use the dot product. it came out to be about 72 degrees i think.
you had to use the vector of the pipeline against a vector of the vertical, say (0i+0j+z) and then use the dot product. it came out to be about 72 degrees i think.
EDIT: IGNORE ME... ON ABOUT THE WRONG PART
8. can anybody remember what they got for the point of intersection between the pipeline and the plane?
9. all i can recall from q7 is that the normal to plane was (1,2,3) and pipeline direction (300,100,100) giving theta=arcos(800/(331.7*rt(14)))=49.9 degrees. so angle to plane is 90-49.9=40.1 degrees. holla if that rings a bell
10. (Original post by underscore57)
all i can recall from q7 is that the normal to plane was (1,2,3) and pipeline direction (300,100,100) giving theta=arcos(800/(331.7*rt(14)))=49.9 degrees. so angle to plane is 90-49.9=40.1 degrees. holla if that rings a bell
That's what I got! They made it quite difficult by not giving us a diagram.
11. How many marks do you think you'll lose if you didn't take the 49.9 away from 90? I meant to do that, I left a space on the paper but forgot to go back to it
12. i can't imagine you're gonna lose more than one mark really considering those angle calculations are generally worth 4 marks by themselves and i think that part was 5 marks maybe?
13. (Original post by underscore57)
all i can recall from q7 is that the normal to plane was (1,2,3) and pipeline direction (300,100,100) giving theta=arcos(800/(331.7*rt(14)))=49.9 degrees. so angle to plane is 90-49.9=40.1 degrees. holla if that rings a bell
It certainly does

Overall, what did everyone think of Paper A? Was it harder or easier than normally, or about the same?
14. Easier.
15. (Original post by Tallon)
Think I did quite well. Hoping for the A*. I don't want to sound too big headed but if anybody has any questions about the exam quote me and ask and I'll try and remember
im hoping for an A * aswell, but i was unsure of the intersection between the plane and the pipeline, can you remember the coordinates you gave?
im hoping for an A * aswell, but i was unsure of the intersection between the plane and the pipeline, can you remember the coordinates you gave?

I don't sorry. It was like 40,40,-20 or something like that? I plugged them back in and it worked anyway.

For the angle, it was sin(theta) = not cos(theta) as well I think.
17. (Original post by Tallon)
I don't sorry. It was like 40,40,-20 or something like that? I plugged them back in and it worked anyway.

For the angle, it was sin(theta) = not cos(theta) as well I think.
ok thanks, thats good news! i think i wrote something similair, fingers crossed
18. (Original post by DeanT)
How many marks do you think you'll lose if you didn't take the 49.9 away from 90? I meant to do that, I left a space on the paper but forgot to go back to it
One
19. (Original post by Tallon)
I don't sorry. It was like 40,40,-20 or something like that? I plugged them back in and it worked anyway.

For the angle, it was sin(theta) = not cos(theta) as well I think.
Oh dear, my coordinates looked different. Does anyone remember what the vector AB was, the coordinate of A was, and the equation of the plane?
20. Coordinates were :

(-80,40,140) or (-80,140,40)

Cant remember which way the 140/40 go. - My maths teacher did the paper today and showed us the answers .

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