Edexcel Mathematics: Mechanics M3 6679 01 - 17 May 2017 [Exam Discussion]

Persevered and have polished off weaknesses - nearly done the solomons and have actually found them worthwile - there was a question where you bascially had to calculate the escape velocity on the moon which I thought was quite interesting. With c.o.m derivations from first principles, say if it is a cone for example, the markscheme formulated the equation of the line and rotated about the x axis. I did it by forming a line, with y-intercept h and rearranged y=mx+ h to get an expression for x i.e. x = (y-h)/m. I then used the formula for rotating about the y-axis and got the same answer - presumably both methods are valid, even though my way wasnt stated in the markscheme? That was solomon B for reference

Do you think the solomon papers are much harder than the normal ones? I completely forgot about solomons lol.

Id say they are pretty much exactly the same, just with a few more abstract questions and think they are surprisingly good - Id recommend them tbh

Someone please help on this ez kinematics question:

http://pmt.physicsandmathstutor.com/download/Maths/A-level/M3/Solutionbank-Heinemann/M3%20Chapter%201.pdf

ExA q11 (Page 11)

I don't understand the very last line - do we simply just take the modulus?

Is this because distance is the magnitude of the displacement?

I will type out the question here:


A particle P is moving along a straight line. When t=0, P is passing through a point A. At time t seconds after passing through A the velocity, v of P is given by v= e^(2t) - 11e^(t) + 15t.

Find:

The distance of P from A when t = ln(3)

Yes, distance is a scalar quantity so we ignore the sign.

Thank you Jigsaw.

Who's that?

some serial killer, I think it was your old dp idk maybe i make mistake.

Anyway how are you getting on with M3?

Yeah it was mine but I got rid of it just now. Time for a change me thinks.

And it's alright I guess, I haven't actually done much M3 recently as I'm still finishing off some other stuff, but after I'm done with that I think I'll do some of the solomon papers as recommended by someone else.

How's it going for you?

From Example 8 of the book in Chapter 1 [Page 11]

You end up factorising: v^2 = 81 - (54/x^2) + (9/x^4)

The book says this is: v^2 = (9 - (3/x^2))^2

But I have v^2 = (3/x^2) -9))^2

Who is right..

They are the same.

Just like 5^2 and (-5)^2 are the same.

Thank you - but the question says to express the final answer as v.

And so the square root of both results are different. They are a reflection of the graph. This is what has confused me.

Do you know a pair of values for v and x? If so, they will only work in one of your two options.

Haha.

Yh its going decent, I like the first four chapters, it is the last chapter which I don't like. It's the first exam and the only exam before break so need to do well :P

Can I ask what learning resources you have used. I have only used the Edexcel book - not much else on net I have uncovered so far.

I went through the textbook, then did a couple of past papers to see which topics I needed to work on, and then worked through some of the questions on Madasmaths on those topics.
I'm not sure if examsolutions has covered much M3 stuff but if he has then I would recommend watching some videos of his, they can be quite helpful.

Ah yes madas, they were amazing for M1

Hi there, for M3 do we need to know what G is? I've seen it in the books but not in exams.