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**Please help....rotational motion**

## Homework Statement

A stuntman swings from the end of 4 m long rope along the arc of a vertical circle. If his mass is 70kg, find the tension in the rope required to make him follow his circular path, assuming he starts from rest when the rope is horizontal:

a) at the beginning of his motion

b) at the bottom of his arc

## Homework Equations

centripetal acceleration = v^2/r

F = mv^2/r

## The Attempt at a Solution

For part a) at the beginning of his motion, is the tension equal to zero? The tension of the rope is pointing to the center and therefore the equation is F = mv^2/r. However, v is equal to 0 because he starts from rest. is that right?

For part b) at the bottom of the arc, tension in the rope and mg causes acceleration and therefore the equation is F - mg = mv^2/r. But what's v???

Can someone help me please?