2016 Unofficial M1 Mark Scheme? 2016

Hi thanks for the replies Klopp can you please do the scale pan question

does anyone remember the details of question 6 such as distances and masses?

Yes:
A non-uniform rod AB has a length of 6m and a mass of 30 kg. It is supported by 2 pivots (or was it 2 strings?) at points S and T, where the distance AS = 0.5m and TB = 2m. When a particle of mass M is attached to the rod at A, the rod is about to tilt about S. When the particle of mass M is moved to B, the rod is about to tilt about T.

Assume the distance between A and the centre of mass is d.
Find:
i) the distance d.
ii) the mass M.

Could someone work out the full solution to Q5 (the one with the coefficient of friction). I vaguely remember I might have said .73 but am not sure anymore and when I tried to reproduce it, I got a totally different value (.37), most likely because I can't remember the numbers correctly.

Thank you,
Diana

does anyone remember the details of question 6 such as distances and masses?

Yes:
A non-uniform rod AB has a length of 6m and a mass of 30 kg. It is supported by 2 pivots (or was it 2 strings?) at points S and T, where the distance AS = 0.5m and TB = 2m. When a particle of mass M is attached to the rod at A, the rod is about to tilt about S. When the particle of mass M is moved to B, the rod is about to tilt about T.

Assume the distance between A and the centre of mass is d.
Find:
i) the distance d.
ii) the mass M.

Could someone work out the full solution to Q5 (the one with the coefficient of friction). I vaguely remember I might have said .73 but am not sure anymore and when I tried to reproduce it, I got a totally different value (.37), most likely because I can't remember the numbers correctly.

Thank you,
Diana

For the SCALE PAN question:
A scale pan of mass 0.5 kg is attached to a string. In the scale pan there is a brick of mass 1.5 kg. The scale pan moves upwards with constant acceleration of 0.5 ms^-2. Find:
a) The tension in the string.
b) The magnitude of the force exerted by the pan scale on the brick (or perhaps the other way around, but it doesn't matter cos they're equal).

if you post question 5 i will do it after ive done 6

Hi, Thanks a lot, but my problem is remembering the values in the question. I can't remember the value of the force and the angles of the plane and force... :/

if you remember as much as you can i can work backwards

i need to know the value of the force acting on the particle, the mass of the particle, and which angle goes where (20 at bottom, 30 on top or 20 at top, 30 at bottom)

Here's what I remember:

A particle P, of mass 2kg, is at rest on a rough inclined plane which makes an angle of 20 degree with the horizontal. It is supported by a force of 40N, which makes an angle of 30 degrees with the line of greatest slope of the plane. The particle is in equilibrium and is about to slide up the plane. The coefficient of friction is u. Find the coefficient of friction.

What I am not sure is whether the values for the mass, angles and force are correct.

I wrote F - uR (where R = normal reaction)
Then:
(Perpendicular to plane): R = 2gcos(20) + 40sin(30)
(Up the plane): 40cos(30) - 2gsin(20) - F = 0
=> F = 40cos(30) - 2gsin(20)

u = F / R.

But if I insert the numbers I gave you above, I don't get .73... so I must be mis-remembering something... or I did it wrong.

Maybe someone else remembers the values given?

Hey guys also for 1(b) p = (400+15t)i + (20t)j
q = (20t)i + (800-5t)j

I wrote p = 400i + t(20j+15i)
and for q = 800j + t(20i-5t)

I saw in mark schemes this is sometimes how they write it, it means exact same thing, do you think I will get full marks for this?

ive uploaded model answer to question 5 under the model answer spoiler

what was question 2?