[godkid308]

(Original post by MHRed)
That actually makes a lot of sense. I did it using WD/t, but I have a feeling your way is the right way.

Unfortunately it's not It would have stated air resistance if that was the case. I Think Rudolf is correct as it you do it through the SI units, 1.02J = 1.02Nm.
1.02Nm / 1.5m = 0.68N. Then as it assumes constant resistance, 0.68N x 5.5ms^-1 = 3.74 Nms^-1 = 3.74 W.

Damn (((((((( Lost 4 Marks!

[TimetoSucceed]

what's the general consensus here, harder than usual?

i think i lost around 10 marks overall lol

[OllieReynolds]

What did people get for the centre of mass question? I got the centre of mass at about x=2.somthing and y= - 2.something. and i got the angle with the vertical at 30.somthing degrees.

Sound familiar?

[TimetoSucceed]

(Original post by OllieReynolds)
What did people get for the centre of mass question? I got the centre of mass at about x=2.somthing and y= - 2.something. and i got the angle with the vertical at 30.somthing degrees.

Sound familiar?

remember y= -3.6, cant remember x but around 2. something i think, 2.14? cant remember

angle was 33.8 if i remember correctly

[OllieReynolds]

(Original post by TimetoSucceed)
what's the general consensus here, harder than usual?

i think i lost around 10 marks overall lol

Yeah i think it was about an average paper, not too easy and not too hard. There were a few questions which were a lot different to any in the past 8 years (e.g. the restitution question). The frameworks was a bit of a trick questions as well... as they didn't give values for the other external components of the framework... but i think you can just ignore them? Since the actual triangle should be in equilibrium within itself (thats the whole point of a framework?).. thats the only question that threw me a little

[Calculator fx]

yeah i got 3.32 for x bar and -3.6 for y bar, and something like 33.8? for the angle but its so annoying in question 2 i took the weight as the mass, but i think from there i was fine, and with the e>0.3 one i forgot to write and inequality, plus i said trb=tbc so many silly mistakes. hope the boundaries aren't too high

[rudolfovic]

my x&y were 2.32 and -3.6
With the framework question you couldn't just ignore all the other joints - you had to consider 2 perpendicular equilibria for A(that would get you AB and AC) and B (through working out BR you can get to BC). The reason you can ignore the rest is because the question only wanted AB, AC and BC not because they are irrelevant

[gymrat]

Did no one get 2.44 for x bar?

And the moments question, no one for 6N and 9N for the first bit?

[rudolfovic]

the moments question is definitely not 6N and 9N - the distance from G to C is 4 times greater than the distance from G to B.. so the moments must be 12 and 3.

[joshgoldman]

(Original post by godkid308)
Unfortunately it's not It would have stated air resistance if that was the case. I Think Rudolf is correct as it you do it through the SI units, 1.02J = 1.02Nm.
1.02Nm / 1.5m = 0.68N. Then as it assumes constant resistance, 0.68N x 5.5ms^-1 = 3.74 Nms^-1 = 3.74 W.

Damn (((((((( Lost 4 Marks!

Yup that's what I got...

I did v^2=u^2 +2as to find the acceleration, then said mg-F=ma, found out what the force was, then did Power=Fv to find the power at that point.

I also didn't write that e obviously has to be <1, but hopefully they might take that for granted?

A mistake I also seemed to make is for work done when pushing the block up the slope. I worked out the vertical distance gained then just said the work done will be equal to the increase in GPE by conservation of energy

[sajawalm]

in the moments question (question 2), the part you had to find the tipping, slide thing.... when the object was placed on the table, was the tension still there? The tension that was at an angle, that you had to find in the part before it (ii), this question was part iii.

[joshgoldman]

Here's my unofficial mark scheme... For the end of question one I used energy and said work done is equal to GPE... But apparently not!


This was posted from The Student Room's iPhone/iPad App

[gymrat]

I just hope I did enough for an E

[TimetoSucceed]

(Original post by joshgoldman)
Here's my unofficial mark scheme... For the end of question one I used energy and said work done is equal to GPE... But apparently not!


This was posted from The Student Room's iPhone/iPad App

yeah i got a lot the same, but i fukd up some easy marks, fml

[MHRed]

(Original post by sajawalm)
in the moments question (question 2), the part you had to find the tipping, slide thing.... when the object was placed on the table, was the tension still there? The tension that was at an angle, that you had to find in the part before it (ii), this question was part iii.

Nope, it had been removed.

[Lydia112]

(Original post by gymrat)
Did no one get 2.44 for x bar?

And the moments question, no one for 6N and 9N for the first bit?

I got those values for the first part too, and I thought I'd got it right but it looks like other people have got different values so I'm not sure which is right.


This was posted from The Student Room's iPhone/iPad App

[joshgoldman]

(Original post by MHRed)
Nope, it had been removed.

I also assumed it had been removed.. It was a little unclear though

[Calculator fx]

impulse -15ns?

[MHRed]

(Original post by Calculator fx)
impulse -15ns?

Yup, that seems the common consensus.

[monkey.]

(Original post by saraj17)
2)(i) tension is string at C is 3N
tension in string at B is 12N

(ii) by taking moments T=20.4N
and by resolving , the magnitude of the force at a is 17.7N(3.s.f) ???

(ii) the force need to be 10N for it to tip
the force needs to be 9.75 for it to slip
so it slips before it tips

3)(i) COM(2.32, -3.6)?
(ii) 33.8 if i remember right

b)diagram
(ii) the stress in AB in 12root3 N (tension)
the stress in AC is (5+6root3)N (compression)
the stress in BC is 36N (tension)

4)(i) 1.5 seconds
(ii) Vp = (3-10e) Vq= 3(1+e)
(iii) 3/10 < e <1
(iv) 6/7 < e < 1
(v) 3ms-1

Your second E is wrong ... it was less than zero ... try subbing your E back in - wont work