Author Topic: Edexcel PHYSICS Doubts  (Read 137932 times)

Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #285 on: January 03, 2011, 02:24:07 pm »
Hello!
I'm confused..What is the difference between the celcius scale and centigrade scale?

Thanks :)


Celsius and centrigrade are two names for essentially the same temperature scale (with slight differences). The centrigrade scale is divided into degrees based on dividing the temperature between which water freezes and boils into 100 equal gradients or degrees. The word centigrade comes from "centi-" for 100 and "grade" for gradients. The centigrade scale was introduced in 1744 and remained the primary scale of temperature until 1948. In 1948 the CGPM (Conference General des Poids et Measures) decided to standardize several units of measurement, including the temperature scale. Since the "grade" was in use as a unit (including the "centigrade"), a new name was chosen for the temperature scale: Celsius.

The Celsius scale remains a centigrade scale in which there are 100 degrees from the freezing point (0°C) and boiling point (100°C) of water, though the size of the degree has been more precisely defined. A degree Celsius (or a Kelvin) is what you get when divide the thermodynamic range between absolute zero and the triple point of a specific type of water into 273.16 equal parts. There is a 0.01°C difference between the triple point of water and the freezing point of water at standard pressure.



Source: http://chemistry.about.com/b/2010/09/20/difference-between-celsius-and-centigrade.htm

Please do correct me if I've posted something wrong. :)
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #286 on: January 04, 2011, 08:21:14 am »
the car thing ;

(a)

(i) As the car is moving forward, there should be a force applied on the road so that the car can move froth, that force is applied by the wheel of the car, power (energy) is given by the engine.

(ii) There is a backward arrow, showing that there is some force acting backwards. This might be due to the friction of the road. This force is faced by the wheel, so it gets the speed.

Otherwise the car will NOT BE SEEN.

by fidato - my friend =]

Thx. I get it now :)
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #287 on: January 04, 2011, 08:25:01 am »
Help me out with this !
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #288 on: January 04, 2011, 08:38:06 am »
And this too! Please! :$

Please!!!!
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #289 on: January 04, 2011, 08:59:48 am »
Explain please?
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #290 on: January 04, 2011, 09:00:33 am »
Will my answer be enough for the 4 marks?
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Offline Vampire-Love4ever

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Re: Edexcel PHYSICS Doubts
« Reply #291 on: January 04, 2011, 09:03:28 am »
The Teacher said its Something Completely New but we need to know it -.-

I hope the Pictures are Not Blurry =]

Attached .

I still didn't get a part :(
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Re: Edexcel PHYSICS Doubts
« Reply #292 on: January 04, 2011, 09:05:25 am »
How to do the bii part????!!! =/
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elemis

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Re: Edexcel PHYSICS Doubts
« Reply #293 on: January 04, 2011, 09:16:45 am »
Energy density = 0.5 * stress * strain

Jm-3 = Pa

kgm2s-2m-3 = kgm-1s-2

kgm-1s-2 = kgm-1s-2

Hence, it is homogenous.

Note that Strain has no units since it is a ratio. Additionally, 0.5 was ignored since it is a constant.

Know your base units.




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Re: Edexcel PHYSICS Doubts
« Reply #294 on: January 04, 2011, 10:07:58 am »
I still didn't get a part :(

You can't see the picture or you don't understand it ?
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Re: Edexcel PHYSICS Doubts
« Reply #295 on: January 04, 2011, 10:24:50 am »
Will my answer be enough for the 4 marks?

her is an Answer that'll get you FULL 4 marks ;)

ELASTIC ;

Elastic Deformation : when a copper is stretched upto elastic limit and then the stretching force is removed , the material will regain it's Original Shape and Size .

Elastic Region : Stress is Directly Proportional to Strain

PLASTIC ;

Plastic Deformation : When the Copper wire is stretched Beyond Elastic limit and if the force is removed , the material will have Permanent extension

Plastic Region : Stress is NOT Directly Proportional to Strain
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Re: Edexcel PHYSICS Doubts
« Reply #296 on: January 04, 2011, 10:33:05 am »
Explain please?

the Question is Wrong , I know it sounds Weird but it's supposed to be at Point B instead of C.

Explanation ;

For a Circular Path :

You Have to move AWAY from the center . You will be Pushed to the left side (direction of motion)

Let me know if you don't get it ?
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Re: Edexcel PHYSICS Doubts
« Reply #297 on: January 04, 2011, 10:35:49 am »
How to do the bii part????!!! =/

Graph : the Lines are STRAIGHT , but I couldn't manage to do that ,Sorry about that.


distance = about 100  -> based on my calculations , so I assume it's 150 ,i'll make it easier for us to draw. ;)


Attached .
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Re: Edexcel PHYSICS Doubts
« Reply #298 on: January 04, 2011, 10:53:39 am »
You can't see the picture or you don't understand it ?

Don't understand :(
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Re: Edexcel PHYSICS Doubts
« Reply #299 on: January 04, 2011, 10:56:35 am »
And this too! Please! :$

Please!!!!

I think the Question is Incomplete , but I'll answer from my copy ;)
 
Weight is 750 N -> value from the Graph in the Question

Attached to show you how I calculated it.

Here's the Drawing:

An Arrow going UPWARDS showing R -> 250    how => 750 N - 300 N = 250 N

An Arrow DOWNWARDS which is LONGER *because she is crouching- i.e exerting MORE force # -> 750 N

# => Weight does NOT change unless he's in another planet.
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