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-   -   How to get tis relation any hints: (http://www.physicsforums.com/showthread.php?t=350266)

sphyics Oct30-09 08:07 AM

how to get tis relation any hints:
 
http://i274.photobucket.com/albums/j...phyiscs/t1.jpg

plz help me :) to get tis relation.

Doc Al Oct30-09 08:12 AM

Re: how to get tis relation any hints:
 
Assuming those vectors add to zero, just add the horizontal components.

sphyics Oct30-09 08:26 AM

Re: how to get tis relation any hints:
 
Quote:

Quote by Doc Al (Post 2417460)
Assuming those vectors add to zero, just add the horizontal components.

:confused: still not clear :confused:

Doc Al Oct30-09 08:36 AM

Re: how to get tis relation any hints:
 
Quote:

Quote by sphyics (Post 2417467)
:confused: still not clear :confused:

Do you have a specific question? Where did this relationship come from? I assume it's part of a larger problem?

Do you know how to find components of a vector? Read this: Resolving a Vector Into Components

HallsofIvy Oct31-09 02:56 AM

Re: how to get tis relation any hints:
 
The statement [itex]T_1= T_2+ T3cos(\theta)[/itex] is only true if, "T1", "T2", and "T3" are the lengths of the vectors shown and the horizontal components sum to 0. (If both T1 and T2 are horizontal and T3 isn't, as shown, the vectors them selves cannot sum to 0.)

Since T1 and T2 are both horizontal, you need to look at the horizontal component of T3. Drop a perpendicular from the tip of T3 to the horizontal. You get a right triangle with angle [itex]\theta[/itex] and hypotenuse of length T3. The horizontal component of T3, T[sub]x[sub] then satisifies [itex]cos(\theta)= T_x/T_3[/itex] so [itex]T_x= T_3 cos(\theta)[/itex].

sphyics Oct31-09 03:24 AM

Re: how to get tis relation any hints:
 
http://i274.photobucket.com/albums/j...phyiscs/t2.jpg

Quote:

Quote by HallsofIvy (Post 2418538)
horizontal components sum to 0.

yes u r right, i was solving a problem on surface tension. For the equilibrium of the drop, the horizontal components must balance each other.

sphyics Oct31-09 03:34 AM

Re: how to get tis relation any hints:
 
Quote:

Quote by Doc Al (Post 2417472)
Do you have a specific question? Where did this relationship come from? I assume it's part of a larger problem?

yes, its a part of a larger problem; problem on surface tension.

Quote:

Quote by Doc Al (Post 2417472)
Do you know how to find components of a vector? Read this: Resolving a Vector Into Components

:approve: yes i know to find components, BTW i appreciate ur help u always replies to my posts; thanks for ur valuable time :smile:

HallsofIvy Oct31-09 09:07 AM

Re: how to get tis relation any hints:
 
Quote:

Quote by sphyics (Post 2418557)
yes, its a part of a larger problem; problem on surface tension.



:approve: yes i know to find components, BTW i appreciate ur help u always replies to my posts; thanks for ur valuable time :smile:

Doc Al's point was "Apply that method (of finding components) and you will answer your own question!"


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