AQA M1 June 2014 Unofficial Mark Scheme

Original post by Doomlar

We were not told mu for the van though, only for the skip, so I was unsure what to do there

Yeah, I worked it out first time for the van having friction, but then reread the question and saw it only said "the coefficient of friction between the skip and the ground is 0.4"
so assumed there was no friction for the van.

For the last part I only did the friction down the slope, I forgot to subtract/add on the weight as well.

How many marks lost do you think this is? At least all the answer ones :frown:

Reply 42

Original post by ramo55

for last question did anyone do: ma=xcos30-mu(mgcos(theta) + xcos60) ? and then subbed in values for m,g, a, and theta to find x?

You did what I did (I think).

We both forgot to subtract the weight down the slope (as well as the friction :frown:

)

Reply 43

ramo55

Original post by edd1234

You did what I did (I think).

We both forgot to subtract the weight down the slope (as well as the friction :frown:

)

how many out of do you think we will get?

Reply 44

Original post by yourwrong

I'm dsylexic so thats a bit mean.... and even if I spelt my username wrong! At least i can fix my error.

"A bit mean"?! you're the one laughing at other people screwing up on their exams!

Reply 45

Original post by ramo55

how many out of do you think we will get?

I was thinking the same, really not sure.
On the one hand you'd have thought we'd get method marks, but then for the mark schemes on older papers, a lot of the method marks are for "forming an equation with x many parts", so I really don't know.
It was only 5 marks so it's not the end of the world. I'd say at least 1 for all the rearranging and maybe another for use of F=ma.

Did you get 177 in the end? I just redid it on paper and got 176.5 --> 177.

Reply 46

ramo55

Original post by edd1234

I was thinking the same, really not sure.
On the one hand you'd have thought we'd get method marks, but then for the mark schemes on older papers, a lot of the method marks are for "forming an equation with x many parts", so I really don't know.
It was only 5 marks so it's not the end of the world. I'd say at least 1 for all the rearranging and maybe another for use of F=ma.

Did you get 177 in the end? I just redid it on paper and got 176.5 --> 177.

so maybe 1/2? meh not bad.

and i must of done it wrong cos i got 346 or something similair.

ohh well, that wasnt bad.

Reply 47

RoseBrilliante

Original post by wilson1098

For finding the forward driving force of the van, did you consider the tension and friction from the tip. So would it be P - T - F = ma?

I did that too :/

Reply 48

Original post by RoseBrilliante

I did that too :/

There was no friction on the van was there?
The question only gave a value for the coefficient of friction between the skip and the ground.

Reply 49

Original post by Namch

There is also a frictional force acting on the van so your answer to 2f is wrong. Apart from that good stuff

Nope - the question only gave a value for the coefficient of friction between the skip and the ground (explicitly said). Said nothing about friction for the van.
Think Doomlar's right, sorry :redface:

Reply 50

RoseBrilliante

Original post by edd1234

There was no friction on the van was there?
The question only gave a value for the coefficient of friction between the skip and the ground.

I subtracted the frictional force of the van and the tension from P, just seemed like the right thing to do at the time :/ Oh well, another 3 marks lost there ey

Reply 51

Millerman

I did the method for 9 marker right but thought that it said the accelerations were the same, yet I've been told they were different. How many should I get for the method?

Reply 52

Original post by Millerman

I did the method for 9 marker right but thought that it said the accelerations were the same, yet I've been told they were different. How many should I get for the method?

It was a really poorly worded question.

It said A and B, blah dee blah, then said have accelerations Xi + Yj respectively.

I almost thought they both had that acceleration, but in the end went with different (so one was accelerating in i, one was accelerating in j).

You never know, they may have "an alternate solution" bit in the mark scheme for how you did it, especially if a lot of people did the same, which I'm sure they will have.

Reply 53

duckwit

Original post by Millerman

I did the method for 9 marker right but thought that it said the accelerations were the same, yet I've been told they were different. How many should I get for the method?

Interesting, lots of my friends thought it said the accelerations were the same, too.

Perhaps this will factor into the mark scheme somehow, as sometimes (if an alternative answer is popular) they even add in a "suppose they did this question incorrectly" bit to be a little more generous.

Grade boundaries?

Original post by Doomlar

We were not told mu for the van though, only for the skip, so I was unsure what to do there

I wrote" [Assuming the van does not experience a frictional force]" under my answer, but I doubt that a comment like that would be necessary.

Reply 56

duckwit

Original post by ramo55

for last question did anyone do: ma=xcos30-mu(mgcos(theta) + xcos60) ? and then subbed in values for m,g, a, and theta to find x?

Yes, I did that too. I forgot (of all the things to miss...) that there was a component of the weight down the slope.

I'm not sure how many marks we'd lose for this, but it could be pretty bad, like -4 marks.

Reply 57

Millerman