# Tension in cord, No mass

1. Oct 18, 2009

### pharoh123

1. The problem statement, all variables and given/known data
While in a car, a rubber ball is suspended by a cord. When the car slows down, the ball forms a 13 degree angle. Find the acceleration of the car when it is slowing down and the tension in the cord.
I found the acceleration of the car, which is 2.3 m/s2 easily but when i try to find the tension, i am left with the unknown on the numerator of both sides of the equation and i cant go further.
2. Relevant equations
In Y
Ty=mg
T*cos x=mg
m=(T*cosx)/g
-------------------------------------
In x
Tx=max
T*sinx=max
m=(T*sinx)/ax
----------------------------------
m=m
(T*cosx)/g=(T*sinx)/ax
what do i do now?
3. The attempt at a solution
see above

Last edited: Oct 18, 2009
2. Oct 18, 2009

### Staff: Mentor

You won't be able to solve for the tension without knowing the mass of the ball.

3. Oct 18, 2009

### pharoh123

i thought so too because the question asks you if it is actually possible to find the tension without the mass. I answered no but in the books answer key, theres actually an answer (its 0.25N).