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ALL CIE PHYSICS DOUBTS HERE !!!

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ashish:

--- Quote from: Ghost Of Highbury~ on October 10, 2010, 06:39:44 am ---Question Attached.

Doubt : (i) (direction)

           2) For a force F of magnitude 150N, determine the force in S1.

I didn't understand the diagram very well. How exactly will the system move if a force is applied to the end of the lever. Also, how are equal forces produced in the strings? Could someone explain please?

--- End quote ---

if the string would no have been there then the disc would have rotated upon itself!

just like opening nuts with a Cylinder Opener Key


2) the moment produce will be equal to the couple ( the two string will have opposite but equal forces)

moment = (30/100)* 150
=45Nm

couple is perpendicular distance  between the 2 forces * magnitude of one force

45=(12/100)*F
F=375N


sorry but i am getting problem while uploading pictures :(

the tension in the string would be toward the disc

ashish:

--- Quote from: ruby92 on October 09, 2010, 11:05:36 am ---thank you:)
I have two more doubts aswell atm.

From gravitaitonal fields:
The radius of the moons orbit is 3.84*10^8, and its period is 27.4 days.Use keplers law to calculate the period of the orbit of a satellite orbiting the earth just above the earths surface.


--- End quote ---

Keplers law T^2 is direcly proportional to R^3

therefore T^2/R^3 = constant

(27.4*24*60*60)^2 / (3.84*10^8)^3 =9.8977*10^-14

let the period be T

T^2 / R^3 = 9.8977*10^-14
T^2 = (9.8977*10^-14)* (6.4*10^6)^3
T = 5093.74 sec
T=1h24min

is that right?

Ghost Of Highbury:

--- Quote from: ashish on October 10, 2010, 07:47:04 am ---if the string would no have been there then the disc would have rotated upon itself!

just like opening nuts with a Cylinder Opener Key


2) the moment produce will be equal to the couple ( the two string will have opposite but equal forces)

moment = (30/100)* 150
=45Nm

couple is perpendicular distance  between the 2 forces * magnitude of one force

45=(12/100)*F
F=375N


sorry but i am getting problem while uploading pictures :(

the tension in the string would be toward the disc

--- End quote ---

k thanks a lot, + rep.

ashish:

--- Quote from: Ghost Of Highbury~ on October 10, 2010, 08:00:51 am ---k thanks a lot, + rep.

--- End quote ---

thanks mate :)

Deadly_king:

--- Quote from: ashish on October 10, 2010, 08:00:25 am ---Keplers law T^2 is direcly proportional to R^3

therefore T^2/R^3 = constant

(27.4*24*60*60)^2 / (3.84*10^8)^3 =9.8977*10^-14

let the period be T

T^2 / R^3 = 9.8977*10^-14
T^2 = (9.8977*10^-14)* (6.4*10^6)^3
T = 5093.74 sec
T=1h24min

is that right?

--- End quote ---

Good job pal :)

keep it up ;)

+rep

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