## Answers

You did not say what the mass M is. As turns out, you don't need to know M to get the answer. First convert the mass to weight, W.

W = Mg

The vertical component of string tension is T cos30 = Mg

The horizontal component of string tension is the centripetal force

T sin30 = Ma,

where a is the centripetal acceleration

Divide one by the other and you get

sin30/cos30 = tan30 = sqrt3 = a/g

Solve for a..

Ok, the radius of rotation is length*sin30 where length is the length of string.

looking at vectors, mg is down, and mv^2/r is outward, so tan30=mv^2/(r*mg)

tan 30= v^2/(length*sin30*g)

but v= 2PI(length*sin30) square that, put it in the equation

tan30=4PI^2*length*sin30/g check that. solve for length of string.

finally, centacc= v^2/r and you can do that algebra..