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Official OCR Physics A G481 24th May June 2016

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Original post by Tforce
I agree with most of this, although factors affecting drag force would be area of parachutist and weight surely?


idk previous ms allowed like 5 different stuff for factors affecting drag for some other papers. i put down top 2 which came into my head ahah
Reply 121
Original post by ludd-sama
Damn, I didn't think of dividing 90 by 4 for the extension question, hopefully I'll only lose 1 mark for that.

Did anyone else say the extension would increase for the very last question?


thats what i did, for the explanation, i said there is a reaction force due to the acceleration upwards which would cause the cables to stretch
Reply 122
Yeah... that google doc is too susceptible to spam
Reply 123
Original post by President J
Thanks but Micrometer would be used for thickness rather than height ?


yes, you find the thickness of the aluminium, then multiply by the given width to find the cross section area (assuming a rectangle like area).
Reply 124
Original post by Siddhart1998
idk previous ms allowed like 5 different stuff for factors affecting drag for some other papers. i put down top 2 which came into my head ahah


I put surface area of downwards face of the parachutist, and air density instead of weight, due to some odd way in which the question was worded of something
Reply 125
Original post by RBoss
I put surface area of downwards face of the parachutist, and air density instead of weight, due to some odd way in which the question was worded of something


I put velocity and air density/temperature for the parachuter question
Reply 126
Original post by sqr00t
yes, you find the thickness of the aluminium, then multiply by the given width to find the cross section area (assuming a rectangle like area).


Did you say that the area had to be re-calculated after every weight addition? I didn't in the end but I guess the aluminium stretches with added weight
Original post by RBoss
Did you say that the area had to be re-calculated after every weight addition? I didn't in the end but I guess the aluminium stretches with added weight


no you don't need to write that
https://docs.google.com/document/d/1qpVGz5RufjRIicXLj5sG75kDpVVmF0b8jWRgD7HG2gA/edit
unnofical mark scheme hopefully being made now, sorry people keep spamming me so gets deleted
How many marks was the last Q??
Extension would decrease as the force increased and young modulus is constant so strain must be less because stress Is higher and young modulus must stay the same so as strain is less extension must be less
any responsible people want to be owners of the mark scheme, put your email pls:

https://docs.google.com/document/d/1qpVGz5RufjRIicXLj5sG75kDpVVmF0b8jWRgD7HG2gA/edit
Reply 132
Original post by 09johnsonda
Extension would decrease as the force increased and young modulus is constant so strain must be less because stress Is higher and young modulus must stay the same so as strain is less extension must be less


Force increase, so stress increased, so as Ym = Stress/strain strain needs to be greater, so extension must increase
Did anyone find that paper easy!?!? I thought it was super hard!!
I got 5 for the bike question, I don't even remember how
(edited 7 years ago)
Reply 135
Original post by Daribig
The extension decreases. Force increases so stress increases so YM increases so strain decreases so extension decreases. Was this right?


was this for the last last last last question? they said the acceleration is upwards, so there would be a reaction force downwards, causing cables to extend.
Original post by qwerzxcv1234569
Did anyone find that paper easy!?!? I thought it was super hard!!


I thought it was better than last year!
Reply 137
Original post by ludd-sama
for the Young's modulus questions. The part where they asked if the guy was wrong for using the breaking point to calculate Young's mod. He was wrong because you have to do it within the linear part right?


bad way of explaining. you just need to say that region where he used is where the elastic limit has been exceeded.
Original post by 09johnsonda
Extension would decrease as the force increased and young modulus is constant so strain must be less because stress Is higher and young modulus must stay the same so as strain is less extension must be less


What question is this for?

And wouldn't it be the opposite, as force is proportional to extension?
Original post by sqr00t
bad way of explaining. you just need to say that region where he used is where the elastic limit has been exceeded.


Yeah I wrote something to the affect of that only applying when the spring is obeying hooked law.

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