AQA Mechanics 2 Unofficial Mark Scheme

On 6b is there suppose to be a constant by e^-t

2ii was 1.26 (cube root of 2), the question was "At what time does F act towards south?" so i component = 0, 2 = t^3, t = (2)^1/3

Think that was part iii, so I think you're right and he's forgotten that part, but 8.2 is the magnitude of the force at t=3 which was definitely one of the questions

I included work against friction in my solution and got 7.5m as my answer

How come?

I didn't have one and on the mark scheme there is one

Yeah think there is, cause you have ln(g - lambda*v) so when you get rid of the logs you still have a lambda so you have to divide through by it

Ah, yep, he's just forgotten a part

7.50 and 4? (reject 4 obvs) I got that but didn't use cos30 to find the frictional force so maybe we made the same mistake?

Yeah I'm saying by the power

Yeah I'm saying by the power

We have the exact same solution. I didn't use cos30 either I don't think, I'd expect us to to get around ⅝ marks on that question then - dropping two marks for not using cos30 (though they may be kind and we may only lose one) and then the final answer mark

Yes there was. It's a common mistake but you had to multiply both sides by -lambda before integrating as the g-lambda*v differentiates to -lambda.


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How many marks would I loose for that

Yeah because when you integrate the left hand side, you have to divide through by -lambda cause of the chain rule, so when you multiply your expression by lambda, t becomes lambda*t

Probably 2/3 out of 6.


Posted from TSR Mobile

I got 7.58
I got x=0 and x=3.58
For last q obv

Mate you're the one pushing all the grade boundaries up, swear you come out of all these exams with a 100% correct mark scheme in 5 minutes XD