# Homework Help: Ball and string

1. Jun 24, 2004

### akatsafa

A 2.4kg ball tied to a string fixed to the ceiling is pulled to one side by a force F to an angle of 28 degrees from the ceiling. Just before the ball is released and allowed to swing back and forth, (a) how large is the force F that is holding the ball in position and (b) what is the tension in the string?

I tried solving this using x and y components, but it's not working. How would I set this up using components?

2. Jun 24, 2004

### Staff: Mentor

Show what you've done. (I assume that the force F is meant to be a horizontal force.) Give the x and y components of each force acting on the ball.

3. Jun 24, 2004

### akatsafa

I know that tension from the string is acting on the ball, its weight*gravity, and the force that i'm trying to find, but with two unknowns, how do i find force and tension?

4. Jun 25, 2004

### e(ho0n3

I know what you're getting at. It seems rather puzzling doesn't it. If you just let F be a force with 0 as the vertical component, you should be able to solve this. My question is, if I don't know the direction of F, how do I solve this problem?

Last edited: Jun 25, 2004
5. Jun 25, 2004

### Staff: Mentor

Remember rule #1: Always do what Doc Al says! (Just kidding... ) But I asked you to find the x and y components of each force acting on the ball. Do it! Then add the x components and set equal to zero; then do the same for the y components. You'll get two equations and two unknowns.

6. Jun 25, 2004

### Staff: Mentor

The magnitudes of the force F and the tension depend on the angle that the force makes. So if you aren't given the direction of F, you don't have enough information.