# Dynamic calculation problem

1. Sep 29, 2009

### puccafan

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

2 kg ball revolves in a horizontal circle with speed of 1.5 m/s. knowing that L= 600 mm, determine (a) the angle that cord forms withe vertical
(b) the tension in the cord
i don't know how to put the figure but this problem is similarly like people practice hammer throwing.
L= 600 mm is distance of the rope

2. Relevant equations

[a][n] = [v][2]/L

3. The attempt at a solution

i got this equation; 7.5+19.62cos θ = T
and 9.81 sin θ =[a][t]

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

2. Relevant equations

3. The attempt at a solution

2. Sep 30, 2009

### tiny-tim

Hi puccafan!

(try using the X2 tag just above the Reply box )
Yes, a = v2/L, where a of course is horizontal (there is no tangential acceleration).

But I don't follow your subsequent equations (you're not assuming that the acceleration is along the string, are you? … acceleration is a matter of geometry, not physics ) …

just resolve T into horizontal and vertical components, and leave g and a as they are.

What do you get?