part i) you need to do is divide 24 hours by the time period to get 14.2 orbits in 24 hours

part ii) we need to find the number of orbits it would take to photograph. So if we find the circumference (6400 x 10^3 x 2pi) and then divide that by 3000 x 10^3 m, we get that it would take 13.4 orbits to photograph the whole of the surface. In part i, we showed that the satellite makes 14.2 orbits in 24 hours so if we compare 13.4 with this figure we can see that the satellite will be able to photograph the whole of the surface in 24 hours

Reply 69

hallo.C

Does anyone know if you need 90% ums in the exams for an A* or 90% across all of A2, including coursework

Reply 70

MahuduElec

Original post by hallo.C

Does anyone know if you need 90% ums in the exams for an A* or 90% across all of A2, including coursework

All of A2, which I helpful if you can get full ums on the CW.

Reply 71

hallo.C

Original post by MahuduElec

All of A2, which I helpful if you can get full ums on the CW.

I got 38/40 on the coursework. What should I be aiming for in the exams?

Reply 72

-Bex-

Original post by hallo.C

I got 38/40 on the coursework. What should I be aiming for in the exams?

39/40 or 38/40 is an A* in coursework

Reply 73

MahuduElec

Original post by hallo.C

I got 38/40 on the coursework. What should I be aiming for in the exams?

Well I'm guessing thats 54 ums, so ou need 90% ums across exams, as you have 90% ums in CW. Assuming got at least a B last year for the total 480.

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Reply 74

alevelup

Original post by TheFarmerLad

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!

thank you so much ! x

Reply 75

hallo.C

Original post by MahuduElec

Well I'm guessing thats 54 ums, so ou need 90% ums across exams, as you have 90% ums in CW. Assuming got at least a B last year for the total 480.

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I have 287 from last year but am less confident this year

Reply 76

MahuduElec

Original post by hallo.C

I have 287 from last year but am less confident this year

You're pretty much in the same situation as me then. D's in the exams to get an A, ~90% in exams for an A*

Reply 77

mjcejnc32

anyone know what to do for sig figs then? ocr are so random, sometimes all the info they give is to 2 but the markscheme says answer is 3 and sometimes it says 2, sometimes standard form and sometimes not???

Reply 78

mjcejnc32

Original post by hallo.C

I got 38/40 on the coursework. What should I be aiming for in the exams?

coursework can be moderated down tho, i got 39/40 last yr and it got moderated down to 48/60 ums cuz of my class i think

(edited 7 years ago)

Reply 79

TheFarmerLad

Original post by rm761

Having just consulted @teachercol on the matter, he recommends leaving final answers to 2.s.f (unless the data is to three) and then for further calculations involving your previous answer, carry 3 s.f forward and then once again leave the overall final answer to two. I personally think that is a silly method - think it would make a lot more sense to carry exact answers forward from previous calculations and then always leave the final answer to 3 s.f. :mad: