AQA MM1B - Mechanics 1 -Tuesday 21st June 2016

you need to think about the components of the velocities.

I component/divided by J component leads directly to direction

so this is the same when the velocities are parallel

Still very hard for M1 and the AS students

SAME horizontal plane only means that they are at the same height, i.e. don't move up or down relative to the ground. The question specifically said "instant" at which the velocities are parallel, which straight away means there's only one value for t - which is 12. The big misconception is really that most people didn't realise that when two velocities are parallel, one is a multiple of the other but they are not necessarily the same magnitude. With your method, if you put t=5 into the expressions for both components of both velocities, you would find that the velocities are neither the same, nor multiples of each other, so could not possibly be parallel.

The key knowledge that AQA were looking for here was that multiples of vectors are parallel, which is GCSE knowledge, not Core 4 (although it is used briefly again in Core 4 with vectors in i, j and k) and that is what made this a 10 mark question when everything else it was asking had come up in 6-8 markers in previous years.

I'm not saying it wasn't a tough question, it was, but that is what they were testing for.

On which exam board for GCSE is this on because I certainly didn't learn it 😂

How did you guys get 1.76 for question 7a. I keep trying and i got 1.9 something... :/

you have to make s=1 and a= -9.8 I think?

I'm an idiot, i made s=-1 for some reason. How many marks would I lose for thatc question, do you think?

ok thanks, I'm a further maths student and managed to do 6x4 = 32 instead of 24 :-(

For the 10 marker I did everything right until working out the position of B where I did not add it's original position vector so I got a distance much smaller then 106 - how many lost?
With the 7 marker I also did everything right until right at the end where I forgot to square the cos50 so I only divided by cos50 not cos^2(50) and so got 10.6 instead of 13.2 - how many lost again?

You can't do 16/1.7 because 1.7 was the time taken for the ball to hit the front edge, you had to rework out the time taken to be 1.9 as it would take longer to go further then do 16/1.9 etc

I'm a bit late but I'm pretty sure it was 081 degrees as it seemed too big so I flipped the opp/adj fraction to ensure it was the most sensible answer and about 7.something degrees came out, confirming it was actually about 081

note: there will still be a fair few method marks for getting that far.

My opinion on boundaries:

Full UMS: 66
A: 51
B: 44
C: 38
D: 32
E: 26

Please don't take this as absolute, it is my prediction, but I am usually accurate when predicting boundaries. Expect something around this.