For question 6(c)(iii) of the June 2015 paper, does the number of moles remain constant? I thought as the tank is being used by the diver the moles will decrease as he/she is using them up.

Would I get the marks for saying P is proportional to n and T, so if temperature and number of moles decrease so does the pressure.

Reply 46

mjcejnc32

Original post by L'Evil Wolf

Ask your teacher, they should be able to give to you.

im an external candidate, don't have a teacher to ask :tongue:

Reply 47

mjcejnc32

someone pls post paper, theres no way for me to get it

Reply 48

MahuduElec

Pm me your email and I'll send the 2015 stuff if you want. Not sure how to send it another way

Reply 49

TheFarmerLad

Hows everyones revision going? Find it quite hard how to revise for this tbh, papers seem easy but there's always that one wordy question that mind****s you haha

Reply 50

TheFarmerLad

Original post by MahuduElec

Pm me your email and I'll send the 2015 stuff if you want. Not sure how to send it another way

Yes please! Do you have G484 and G485 June 2015?! That would be extremely helpful

Reply 51

MahuduElec

Original post by TheFarmerLad

Yes please! Do you have G484 and G485 June 2015?! That would be extremely helpful

Google Drive Link: https://drive.google.com/open?id=0B989KkRnVfa7NW50NXdzTllLc1U

Reply 52

TheFarmerLad

Original post by MahuduElec

Google Drive Link: https://drive.google.com/open?id=0B989KkRnVfa7NW50NXdzTllLc1U

Hero, thank you!

Reply 53

EpicNameBro

Original post by TheFarmerLad

Hows everyones revision going? Find it quite hard how to revise for this tbh, papers seem easy but there's always that one wordy question that mind****s you haha

Feel exactly the same way. Most questions in the paper seem easy but when I do the actual paper they do not feel easy at al

Reply 54

motassks

Quick question about the c) part:

(Earth: radius: 6400km, mass= 6x10^24kgMoon: radius: 1740km, mass 7.4x10^22, distance from Earth: 3.8x10^8m)

Using the data provided at the start of the homework questions calculate:
a) The Earth's gravitational field strength at the moon
b) The gravitational force exerted by the Earth on the moon
c) The magnitude of the Moons acceleration towards the Earth

Is c) just same answer as a), or is it the answer of for a) and b) added together?

Reply 55

hallo.C

Original post by motassks

I would use F=Ma on your answer for part b, dividing by the mass of the moon

Reply 56

alevelup

Hi, can anyone please help with question 3c on Jan 2011 paper ? As usual the mark scheme doesnt help me in understanding what the graph should actually look like, and why. Thank you so much !! (Paper and mark scheme attached below) xx

http://www.ocr.org.uk/Images/61757-question-paper-unit-g484-the-newtonian-world.pdf
http://www.ocr.org.uk/Images/63666-mark-scheme-unit-g484-the-newtonian-world-january.pdf

Reply 57

TheFarmerLad

Whats the rule on sig figs? Does your answer have to be the same number of sig figs as the values used in the question (almost always 2) or can we leave it as 3? Tend to find I'm losing marks because I'm carrying my exact answer forward in the following questions that involves the value I previously calculated...

Reply 58

TheFarmerLad

Original post by alevelup

Bear in mind that the gradient of the graph is equal to the rate of loss of temperature and remember thermal energy is directly proportional to temperature. C (SHC) of milk below 0 degrees is significantly less than it is above 0 degrees therefore, less thermal energy required (to be lost) in order to cool it down below 0 degrees than above 0 degrees. In other words the gradient of the graph below 0 will be greater than that above 0. If less energy is required to cool a substance, the rate of temperature decrease (gradient) will be greater. And for the final mark, temperature will remain constant at 0 for a short while as this is the point of the substance changing state (we're told the freezing point) - remember internal energy? So to sum up, gradient of graph will be negative always (apart from when the temp remains at 0, there it will be a straight line) however gradient below 0 will be steeper than above 0. Hopefully all that helped!

Reply 59

MahuduElec

Original post by TheFarmerLad

Well I just did the Jan 12 paper, and pretty much, nearly every answer in the ms was 3sf. So I'm probably going to do 3sf unless it's clear the Q has 2sf throughout all parts.