# Tension problem involving Centriptal force

#### Lucky14

I am having a tough time solving this problem where a mass, connected to two strings with equal distance fixed to a stick, rotates around the stick at a given speed and i need to solve for tension in both the upper and lower string.
Looks like this
http://www.webassign.net/pse/p6-11.gif

What i really need to know is how the weight vector of the mass is reflected in the tension.

Last edited:

#### whozum

I guess the most subtle but improtant hint would note that there is no acceleration in the y direction... from there you can list your forces and solve the system of equations.

#### Lucky14

i know the net force on the y-axis is equal to zero and the tension must somehow balance both the weight of the object and the centriptal force of the object. My real trouble is that i think that the higher string is supporting all of the weight of the object but i keep getting the wrong answer. Does anyone know how the force of the objects weight is reflected in the tension forces.

#### Doc Al

Mentor
Lucky14 said:
Does anyone know how the force of the objects weight is reflected in the tension forces.
It seems like you want to write the answer directly, solving it in your head. Don't! Instead, label the forces, apply Newton's 2nd law, and solve for the tension in each string.

Call the tension in the strings $T_1$ (top) and $T_2$ (bottom). What are the components of the tensions in the x and y directions? You realize that the net force in the y-direction must be zero: Good! What must the net force in the x-direction equal?

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