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physics ocr ffe and synoptic - how'd they go? watch

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    i said that 10ms/s was for an olympic runner, so about 5ms/s for a GOOD runner
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    could 30/60 be an A?
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    i said heating water on a ring is slower coz it heats first by conduction through pan then by convection in water- this overall tkes longer whereas with microwave it immediately increases the ke of all the particles and so the tempt pretty much increases straight away. i said thecasserole is best ona hot plate coz theres not much water in a casserole heh and the hotplate will actually heat all parts of the casserole. heh - turned into waffle by the end though!
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    my answer to that long microwave question was along these lines:

    conventional ovens and hotplates take time to heat up, so are inefficient to start with, but become more efficient later on. Microwaves start heating immediately and can penetrate into the food, cooking it throughout, rather than from the outside-inwards (like in a conventional oven).

    However, for a large casserole, when the hotplate has warmed up, it will transfer more power to the food than a microwave - so will heat a large amount of food quicker in the long run.

    i've checked with my physics teacher and my answer (above) he said might just get me the 5 marks...i apparently got the gist of it, i might have missed a minor point, but cant tell without the mark scheme.

    (Original post by ThunderCat8)
    1/r^2...is that exponential graph? The one with the constant half life that never reaches zero? If so, yay! I did that!

    For me I did:

    1) Directly propotional straight line up going through origin
    2) Starts high, goes downwards, and then falls to zero rapidly when weed is fully pulled out.
    3) Exponential
    4) Straight line starting high, finishing low.
    5) Exponential

    I had to guess 1,2 and 4, so hopefully I've at least got 3 and 5 right!
    YAY!!!!!!
    but not for 1), at first i did what u did, then changed it

    (Original post by friday13th)
    i said that 10ms/s was for an olympic runner, so about 5ms/s for a GOOD runner
    just take it from a 100 metre sprint, speed = distance over time


    so 100 / say i dunno 12 secs?

    which is about 10 ms-1

    (Original post by chats)
    one question said show the graph is exponential. what you meant to write? i just wrote it never reaches zero and you have to draw a tangent for the gradient???
    what do people think theyve got out of the 510 marks theyve done already?
    hehehe yep, never reaches to zero and i did a calculation
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    To show it was exponential, I worked out that it had a contstant half life throughout. That is right isn't it?

    I remembered our kettle is 2kW, so that is what I put! I said 240 * 10A is about 2000W. Complete ******** there!

    I worked out that 70mph is about 30ms^-1.

    The hardest one out of those was the last one about number density of particles in atmosphere. Very strange indeed! There was another evil "work out how many moles" question that threw me later in that paper. That is like the easiest part of chemistry, but is always really hard when in a physics paper! I worked out if I get about 55% in each of the papers, I can still get a B. So there is still hope for me!

    Cosmology next week will be hard too...we only briefly covered that in lessons...eek!

    (Original post by ThunderCat8)
    To show it was exponential, I worked out that it had a contstant half life throughout. That is right isn't it?

    I remembered our kettle is 2kW, so that is what I put! I said 240 * 10A is about 2000W. Complete ******** there!

    I worked out that 70mph is about 30ms^-1.

    The hardest one out of those was the last one about number density of particles in atmosphere. Very strange indeed! There was another evil "work out how many moles" question that threw me later in that paper. That is like the easiest part of chemistry, but is always really hard when in a physics paper! I worked out if I get about 55% in each of the papers, I can still get a B. So there is still hope for me!

    Cosmology next week will be hard too...we only briefly covered that in lessons...eek!
    yes i said that its an expo cuz it never reaches zero, and did the same kind of calculation u did

    for the kettle i did an amp of 5 x by 240

    number of moles = mass / molar mass <- i used that in one of the papers, somewhere lol
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    Those questions on the UC paper were silly.

    My answer for the kettle power was 3kW. I know this is right for sure because we recently bought a kettle and the Argos catalogue says it's a 3kW rapid-boil model. This was my explanation in the exam.
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    Going back to the graphs, wasn't the 4th one inversely proportional (ie y=1/x)? Surely this would have to be a graph similar to 3 and 5, just a smoother curve?
 
 
 
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