Breaking tension, and a weight component

[Michael805]

I have 2 questions, here is the first:

Homework Statement

A 1.31kg mass attached to a light string rotates on a horizontal, frictionless table. The radius of the circle is 0.402m, and the string can support a mass of 34.6kg before breaking.
The acceleration of gravity is 9.8ms^2.
What maximum speed can the mass have before the string breaks? Answer in units of m/s.

Homework Equations

a=v^2/r
m(v^2/r) > T

The Attempt at a Solution

I tried plugging numbers into the equation v=sq rt(Tr/m), or sq rt((34.6)(.402)/1.31), which is sq rt(~10.61770992) or ~3.26. The assignment said this was wrong (it's online), so I'm not sure where I went wrong.

My next question is this:

I'm pretty sure the equation to solve this is mgsin(theta), but I'm not sure what Mg in the picture is. I've tried both (Mg)(g)(sin(theta)) and just Mg(sin(theta)), but neither have been right. So, I'm wondering what exactly Mg is supposed to be? Or if I'm just using the wrong equation for the problem.

Thanks for the help.

 

[LowlyPion]

I have 2 questions, here is the first:

Homework Statement

A 1.31kg mass attached to a light string rotates on a horizontal, frictionless table. The radius of the circle is 0.402m, and the string can support a mass of 34.6kg before breaking.
The acceleration of gravity is 9.8ms^2.
What maximum speed can the mass have before the string breaks? Answer in units of m/s.

Homework Equations

a=v^2/r
m(v^2/r) > T

The Attempt at a Solution

I tried plugging numbers into the equation v=sq rt(Tr/m), or sq rt((34.6)(.402)/1.31), which is sq rt(~10.61770992) or ~3.26. The assignment said this was wrong (it's online), so I'm not sure where I went wrong.

My next question is this:

I'm pretty sure the equation to solve this is mgsin(theta), but I'm not sure what Mg in the picture is. I've tried both (Mg)(g)(sin(theta)) and just Mg(sin(theta)), but neither have been right. So, I'm wondering what exactly Mg is supposed to be? Or if I'm just using the wrong equation for the problem.

Thanks for the help.

In 1) the force it breaks at is 34.6kg*(9.8) N. They only gave you mass.

In 2) Mg is megagram is 1000kg

 

[Michael805]

In 1) the force it breaks at is 34.6kg*(9.8) N. They only gave you mass.

In 2) Mg is megagram is 1000kg

Correct on both accounts, thank you very much. :)