M1 OCR (Not MEI) Exam - 9/06/2015

Are the answers to force question (question 5) definitely:5i) 1.04 [3]5ii) 1.06 [3]5iii) a=0 [3]5iv) a=0 [2] ?These were the answers I got too but there is some debate whether it was push/pull, did it matter? if not can someone explain why it doesn't.Thanks!

lot of confusion about whether the forces in 5 were pushing or pulling, look at this:



the question stated the angle was above the horizontal, if you take it as pushing down on the block (which would give a negative vertical component) you would be wrong - the angle it makes is below the horizontal.

so it doesn't matter whether or not it's pushing or pulling, just that the angle is above the horizontal. If your force looked like either A, you should be right.

(i think)

as long as your angle is above the horizontal it should be fine

as long as your angle is above the horizontal it should be fine

That's the right concept and method.
However when they coalesce their mass is 2m, therefore the equation is 68m-54m=2mv

Sugar! I got no marks on question 4 at all and maybe like, 3 on question 5. But apart from 1iii I am certain I got absolutely everything else right.

With 1iii I ended up with a quadratic(!) which I used the Eqn feature on my calculator to solve instantly and ended up with an answer of 0.6 exactly.

Surely you got different values for a if the force was pushing rather than pulling as R would be greater

What would 50/72 be as a grade and UMS mark?

Also, would I get method marks if I've done the correct method but with the wrong values??

How many marks would I lose if I had 68m-54m=mv?

I got a quadratic too. I solved it, ended up with 0.5 something, and 5. something. So I chose to reject the 0.5 something and state the answer was 5. something. But looks like i should have rejected the other one and stated 0.5something

That's exactly what I thought, it seems to me that the resultant calculated from the different ways produces different values?

Exactly, so both cannot be right. I has to be one or the other

You can do either, it makes no difference

as long as the angle was above the horizontal, it does not matter

I ended up with 0.8-something and -3-something. I rejected -3-something and used the 0.8-something. Then I worked out time to fall 30m, which was 1.4-something. Took 0.8-something off that which gave me exactly 0.6. Though maybe if I didn't round I would have good the 0,598 that everyone else got.

Hopefully I'll still get 2 marks for getting 0.6. I dunno though, I might have got 0.6 by fluke with totally wrong method so they might not allow it at all. In which case, low B here I come!