What Causes Tension Changes in a Vertical Circle Motion?

[matthayzon89]

Homework Statement

A 0.22-kg ball on a stick is whirled on a vertical circle at a constant speed. When the ball is at the three o'clock position, the stick's tension is 19 N.

Homework Equations

mass m = 0.22 kg
tension in 3'o clock position T = 19 N
tension in 12 'o clock position T ' = T-3mg
= 19 - 6.468
= 12.532 N
tension in 6 'o clock position T " = T + 3mg
= 19 + 6.468
= 25.468 N

The Attempt at a Solution

Can someone please help me understand where the [6.468] came from?

 

[aftershock]

Homework Statement

A 0.22-kg ball on a stick is whirled on a vertical circle at a constant speed. When the ball is at the three o'clock position, the stick's tension is 19 N.

Homework Equations

mass m = 0.22 kg
tension in 3'o clock position T = 19 N
tension in 12 'o clock position T ' = T-3mg
= 19 - 6.468
= 12.532 N
tension in 6 'o clock position T " = T + 3mg
= 19 + 6.468
= 25.468 N

The Attempt at a Solution

Can someone please help me understand where the [6.468] came from?

You said yourself T' = T-3mg

mg = 2.156 so 3mg is 3 times that which gives you 6.468