Qualification > Sciences
ALL CIE PHYSICS DOUBTS HERE !!!
$!$RatJumper$!$:
--- Quote from: TJ-56 on November 07, 2010, 01:18:10 pm ---Im finding it difficult to 'spread the love' deadly king, i will +rep the moment i can do so,
I have a question, regarding a drawing again pls
November 2005 paper 2 q8 (b) (ii) (last question)
can you draw it for me pls? the mark scheme is rly confusing me
thank you so much
--- End quote ---
The equation for Gravitational Potential Energy is: mgh. Now it says that a ball is falling vertically through the air. Which means, that it was initially dropped mid air and is thus falling towards the ground.
From this we can conclude that since it is falling towards the ground, its height above the ground is decreasing as it falls closer. We also know that the mass "m" of the ball and the gravitational feild strength "g" are constant and do not change. So the only thing changing is the value of "h" in the equation. Since it is decreasing and everything else staying constant, the value for the Gravitational Potential Energy will decrease as a result.
This is why the mark scheme says negative gradient because the value for Gravitational Potential Energy is decreasing. Since it was at its maximum height when it was dropped, it will have maximum Gravitational Potential Energy thus the line starts at the maximum y intercept above Ek and ends at h0 on the x-axis.
TJ-56:
--- Quote from: $!$RatJumper$!$ on November 07, 2010, 01:29:08 pm ---The equation for Gravitational Potential Energy is: mgh. Now it says that a ball is falling vertically through the air. Which means, that it was initially dropped mid air and is thus falling towards the ground.
From this we can conclude that since it is falling towards the ground, its height above the ground is decreasing as it falls closer. We also know that the mass "m" of the ball and the gravitational feild strength "g" are constant and do not change. So the only thing changing is the value of "h" in the equation. Since it is decreasing and everything else staying constant, the value for the Gravitational Potential Energy will decrease as a result.
This is why the mark scheme says negative gradient because the value for Gravitational Potential Energy is decreasing. Since it was at its maximum height when it was dropped, it will have maximum Gravitational Potential Energy thus the line starts at the y intercept and ends at h0.
--- End quote ---
thanx +rep that cleared it up
just one last point, why does it start from above the maximum kinetic energy as stated on the ms?
$!$RatJumper$!$:
Thankx for the +rep :)
It starts above because it has the maximum possible gravitational energy when it is at its maximum point just as it is released. The point is, that you need to start your negative sloping line right at the top of the y-axis just to show the examiner that you understand it is at its maximum energy initially. It has to have nothing to do with the kinetic energy because they are separate things. Yes, they are related, but not in such a way that they need to start at the same point.
TJ-56:
--- Quote from: $!$RatJumper$!$ on November 07, 2010, 01:39:33 pm ---Thankx for the +rep :)
It starts above because it has the maximum possible gravitational energy when it is at its maximum point just as it is released. The point is, that you need to start your negative sloping line right at the top of the y-axis just to show the examiner that you understand it is at its maximum energy initially. It has to have nothing to do with the kinetic energy because they are separate things. Yes, they are related, but not in such a way that they need to start at the same point.
--- End quote ---
thanx alot, i finally got it!
$!$RatJumper$!$:
Im glad :)
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