Calculating Tension of a bob moving in horizontal circles

[junkie_ball]

Could someone please look at the problem below and see if i am on the right lines of solving it? I am finding the whole subject of circular motion hard to get my head around and therefore not 100% confident in my workings. I have also attached my free body diagram.

Homework Statement

Calculate the tension in a 3m string attached to a 3kg bob that is moving in horizontal circles of 0.6m radius

Homework Equations

Tanθ = Opposite/Hypotenuse

TCosθ = mg

The Attempt at a Solution

θ = Tan-1 0.6/3
θ = 10.32°

TCosθ = mg
T = mg/Cosθ
T = (3Kg x 9.81) / Cos 10.32
T = 29.91 N

 

[Doc Al]

θ = Tan-1 0.6/3

The radius over the hypotenuse would equal sinθ, not tanθ.

Other than that, you're doing fine.

 

[junkie_ball]

The radius over the hypotenuse would equal sinθ, not tanθ.

Other than that, you're doing fine.

Thanks for that i have just noticed i used TAN not SIN for my workings myself which obviously changes my final answer slightly. Thanks for the reassurance I'm on the right track. I have spent many long hours trying to get my head around this whole subject.