Centripetal accel

1. Dec 3, 2005

jesuslovesu

Here's a picture http://img215.imageshack.us/my.php?image=physics6ry.png

A .10kg ball is on a string in vertical circular motion with a radius .80 meters and the whole system is above the ground .20 meters At the top the tangential velocity is 6.0m/s.

I'm wondering if these are correct:
1)At the lowest point on the circular path the tangential velocity is 2.0 m/s.
2)The tension at the top of the circular path is ~2.6 N

I found the velocity by using KE = PE
I found the tension of the top by: T = Fc + Fw

The reason I'm wondering this is because I figured out the speed, and tensions on the top and bottom and I came up with a higher tension in the top than in the bottom...

2. Dec 3, 2005

andrewchang

At the top, the tension and weight are acting in the same direction:
T + Fg = mv^2 / r
so then:
T= mv^2/r - Fg

3. Dec 3, 2005

andrewchang

In addition, for part A, the ball has both kinetic energy and gpe at the top, while at the bottom it should only have gpe.