Physics: Post your doubts here!

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Manobilly

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I have a tiny question in elastic collisions ,if one particle stops and other moves is it elastic? And if both move thn?
 
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1597.2217

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Manobilly said:
I have a tiny question in elastic collisions ,if one particle stops and other moves is it elastic? And if both move thn?
Click to expand...


In inelastic collision, the momentum is conserved and Ek is lost. In elastic collisions, both values are conserved. Just remember that most of the collisions are inelastic except for in nuclear reactors which is elastic. You can calculate the Ek by 0.5 x m x v^2 for before and after collision if you're unsure about it.

Good luck!
 
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Kyusam

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6Astarstudent said:
ok first you find the wavelength λ which is 2x the distance between 2 antinodes X and Y. so
λ= 2x 33cm = 66cm = 0.66m
and then v=f λ so f= v/ λ=330/0.66=500
we know that period (T) = 1/f = 1/500 = 0.2ms for 1 oscillation
so answer is B
Click to expand...
Thank you so much :D so so much
 
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1597.2217

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How was the exam?

hahahahahahahahaha......... There was a bad overall from my center, I expect between 25-30 myself. Left 4 due to time, 18, 23, 36 and another I cannot remember. Just randomly marked at the end, hoping that all of them are right.
 
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Imran Aasaf Kahout

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My question is somewhat odd and not related to any notes.

The problem is that i forgot to shade my candidate number on the physics multiple choice answer sheet and that has really got me worried. Though my name was written and i did sign, i can't get rid of this gnawing feeling at heart that my test may not be marked.

Does anybody here have had the same experience as me or knows what happens when a situation like this occurs?
 
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1597.2217

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That is bad. The computer will reject the paper and it will be manually graded. It depends on the examiner if he deducts five penalty marks or none. You can just pray now :)
 
Muhammad Harris

Muhammad Harris

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I'm taking AS this oct/nov session. I need someone to help me with the following questions.
Here are the questions: oct/nov 2010 paper 13
Q2,3,5,12,17
Thanks in advance.
 
waleedsmz

waleedsmz

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Muhammad Harris said:
Here is the link for the previous post. Hope anyone can help me.
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Muhammad Harris said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_13.pdf
Click to expand...


2) The time period of the wheel is 0.02s. To show it clearly on an oscilloscope you'd need 0.01s/cm, which is B.

3) Large systematic error means that there is an error in the tools you're using for example, so it measures a completely different value from what you're trying to reach. This cancels A and B. Small random error means that the readings have a small difference between them, so the answer is C.

5) The function is increasing ( with a decreasing rate ). So the difference between the function values ( Y axis ) intervals as the X increases, actually decreases.

In other words, if you draw tangents to the curve you'll find that they're getting less steep as the function continues. This again, indicates that the difference between 8 and 7 for example, is smaller than the difference between 2 and 1 (at which the curve is steeper). So the answer is C.

12) You need a relation that puts final speed, initial speed, acceleration and distance since those are the given ones.
V^2 = U^2 + 2as is the required one. V = 0 in both cases.
u^2 = -2ax ( notice that a is negative since it's deceleration )
(1.2u)^2 = -2aS
divide the two equations to find the value of S. It'd give C.

17) I don't really get this question to be honest. But it's dealing with the rate of change of energy ( aka power ). So I assume A and B are neglected, which leaves us to C and D. C completely ignores the other mass so it can't possible be the answer, since the motor should have higher power if it'd lift the elevator without the supporting mass. So the answer is D.
 
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balay

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Q. How much the momentum of a body would increase by increasing the K.E by 300%?...........the ans is 100%.....but could someone please explain to me the method to solve this question.....would appreciate it a lot!
 
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