Author Topic: Physics help!  (Read 11858 times)

Offline cooldude

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Re: Physics help!
« Reply #75 on: August 26, 2010, 03:29:04 pm »
yeah I figured that....didn't really notice what they were asking for.  :-[

Ah...one more question

June 2010 paper 4 variant 1, Q3 b) How can they say acceleration is constant ? :S Is it because a=g ? :-\

yeah in a way, well the component of the weight that acts down is mgsinx, let x be the angle between the inclined plane and the ground, so mgsinx=ma
so a=gsinx, x is the same for both and g is a constant therefore the acceleration is constant and therefore it cant be shm as a varies with the displacement

nid404

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Re: Physics help!
« Reply #76 on: August 26, 2010, 03:30:14 pm »
yup component of g I meant...ohk just confirming...thanks  :)

nid404

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Re: Physics help!
« Reply #77 on: September 10, 2010, 04:49:19 pm »
With reference to capacitors, can someone explain what 'smoothing' is?

Offline M-H

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Re: Physics help!
« Reply #78 on: September 10, 2010, 09:57:38 pm »
Yeah capacitors smoothen AC.  As in think of it, the capacitor is charged during the positive cycle, while it discharges during the negative cycle. the discharging and charging takes up time...that way, the discharging and charging do not happen at equal intervals..eventually, a graph that would be normally with distinct waves, with a capacitor, you can see it becoming for even.

Sorry, this is a rough explanation. hope it helped.

nid404

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Re: Physics help!
« Reply #79 on: September 11, 2010, 06:09:57 am »
Uhm...Can you get me a graph please  ;D Visualizing this is beyond the capacity of my cat brain  :P Physics doesn't go well with me  ::)

nid404

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Re: Physics help!
« Reply #80 on: September 11, 2010, 06:57:50 am »
And yes Where can I find notes on Application of Physics?

I DO HAVE the CIE Application Booklet for reference(which is pretty useless)

Thank you

Offline M-H

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Re: Physics help!
« Reply #81 on: September 11, 2010, 09:31:56 am »
i'll try to get you sth!! haha, its okay! cat brains :P

Hey, what i usually do for finding out about the applications- i look it up on wikipedia!
Like for capacitors, one important application is, charged coupled devies...so just find out and they explain how the actual thing happens!

nid404

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Re: Physics help!
« Reply #82 on: September 11, 2010, 10:18:12 am »
Wikipedia ahan...okay I'll go through..thanks  :)

Offline M-H

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Re: Physics help!
« Reply #83 on: September 11, 2010, 01:30:36 pm »

Offline M-H

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Re: Physics help!
« Reply #84 on: September 11, 2010, 01:38:13 pm »
Hey, the only difference between the things mentioned in the link i provided and AC, is, that AC have both negative and positive cycles. During the positive cycle, a capacitor is charged, but during the negative, it discharges. 

nid404

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Re: Physics help!
« Reply #85 on: September 11, 2010, 01:45:10 pm »
Well smoothing is the same as having a rectifier with capacitor filter right?

Offline M-H

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Re: Physics help!
« Reply #86 on: September 11, 2010, 02:03:23 pm »
No a rectifier would cut the negative cycles. Its the time that's taken up by the discharging and charging that makes the time interval different, and therefore, your wave is not the same as before. it would become less steep. Eventually, by becoming more and more shallow, its becoming smooth and even!

nid404

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Re: Physics help!
« Reply #87 on: September 11, 2010, 02:08:36 pm »
Uhm...if it's an alternating current, the graph would be different. The graph you showed me is one with a full wave rectifier and a capacitor filter.

Offline M-H

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Re: Physics help!
« Reply #88 on: September 11, 2010, 10:40:19 pm »
Urgh...i...

Alright..i'll look for something to explain my bit hopefully soon!

nid404

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Re: Physics help!
« Reply #89 on: September 12, 2010, 04:54:04 pm »
I've figured it...thanks for your help though  :)