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**1. The problem statement, all variables and given/known data**

A mass of 6.10 kg is suspended from a 1.51 m long string. It revolves in a horizontal circle as shown in the figure

.http://capa2.cc.huji.ac.il/res/msu/physicslib/msuphysicslib/11_Force_Motion_Adv/graphics/prob03_pendulum.gif

The tangential speed of the mass is 3.24 m/s. Calculate the angle between the string and the vertical.

**2. Relevant equations**

F=mv^2/R

**3. The attempt at a solution**

The F component at y is:

Tcosa-mg=0

Tcosa=mg

T=mg/cosa

The F component at x is:

Tsina=ma

Tsina=mv^2/R

R=lsina

mg*sina/cosa=mv^2/lsina

lmgsin^2a=cosamv^2

lgsin^2a=v^2cosa

sin^2a=1-cos^2a

after putting all the numbers i get a final equation which is

10.798cos^2+10.4976cosa-14.798

the solution of the equation was

1-0.78

2-1.753

ofcourse i take the first one

BUT!!!!its not correct!

pleasew tell me where i was wrong

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