Net force of two forces in a ring

ShizukaSm
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Homework Statement


Consider the following ring:
DELETEME.JPG

Considering that [itex]\theta = 30°[/itex], determine F1 and F2 in order for the net force to be oriented downards with magnitude 10^3 N and without any horizontal component.

The Attempt at a Solution


Alright, so, the problem is I find two conflicting solutions when solving this simple problem.

Solution 1:
[tex] \\<br /> \sum F_x = 0 \rightarrow F_1*Sin(20)-F_2*Sin(30)=0 \\<br /> \sum F_y = 0 \rightarrow F_1*Cos(20)+F_2*Cos(30)=1000<br /> \\ \rightarrow F_2 ({\frac{Sin(30)}{Sin(20)} + Cos(30)}) = 1000<br /> \\ \rightarrow F_2 = 429.56N | F_1 = 627.91N[/tex]
PS: How do I fix my parenthesis in line 3 of my latex equation? It's lacking proportion.

Solution 2(Book solution):
Solution2.JPG


So... In short, why aren't those two solutions agreeing?
 
Last edited:
on Phys.org
ShizukaSm said:
[tex] \\<br /> \sum F_x = 0 \rightarrow F_1*Sin(20)-F_2*Sin(30)=0 \\<br /> \sum F_y = 0 \rightarrow F_1*Cos(20)+F_2*Cos(30)=1000<br /> \\ \rightarrow F_2 ({\frac{Sin(30)}{Cos(20)} + Cos(30)}) = 1000[/tex]
Check that last step.
PS: How do I fix my parenthesis in line 3 of my latex equation? It's lacking proportion.
Try using \left( etc. instead of just (.
 
haruspex said:
Check that last step.

Try using \left( etc. instead of just (.

Ahh, got it, can't believe I made such a stupid mistake. I checked and re-checked many times but couldn't spot it myself.

If anyone's wondering, it was supposed to be [itex]\frac{F_1*(Sin(30)*Cos(20)}{Cos(20)}+...[/itex]
 
Last edited:

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