What is the tension in the string at the top of the ball's path?

[Toxage]

Homework Statement

Picture: http://img151.imageshack.us/img151/9393/physicszn8.jpg

A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 60.0 cm, as shown in Fig. 5-33. Its speed is 4.00 m/s and its mass is 0.300 kg.

(a) Calculate the tension in the string when the ball is at the top of its path.

Homework Equations

EF = ma

The Attempt at a Solution

EF = ma
Ft + Fg = ma
Ft = mac - Fg

Ft = ((mv^2)/r)) + mg
Ft = 8 - 5.88
Ft = 2.12

This answer is incorrect.

 

[thejinx0r]

Recalculate mg.

;)

 

[Toxage]

Recalculate mg.

;)

Wow, I made a huge mistake... I had .6m * 9.8m/s^2 for mg... lol

New MG

0.300kg * 9.8m/sec^2 = 2.94.

8 - 2.94 = 5.06 N.