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## Homework Statement

A 0.2kg mass is tied on the end of a 1.6m long string and whirled around a circle that describes a vertical plane.

a) What is the minimum frequency of rotation needed to keep the mass moving in a circle?

b) Calculate the maximum tension in the string at this frequency.

Givens=

mass=0.2kg

r=1.6m

f=frequency which is unknown

## Homework Equations

f=ma

a=4(pi)^2rf^2

f=4(pi)^2rmf^2

a=v^2/r

## The Attempt at a Solution

Im stuck on the fact that i only have two givens and i don't seem to be able to use two equations as it solves one variable, but introduces a new one.

FBD

(top) Fc-mg<------(0.2kg)-------> mg+Fc (bottom)

Part b) is easy to solve once a) is done as i know the highest tension on the string will be at the bottom of the loop where the tension equals mg+ the centripetal force

It would be appreciated if somebody could guide me in the right direction for part A