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## Homework Statement

An object of mass 2 kg is held in circular motion by a string of negligible mass.

Initially the radius is 1 m and the tangential velocity is 4 m/s. The string is

subsequently let out gradually until the radius doubles to 2 m. There are no

frictional or resistive forces present. What is the final tangential velocity?

## Homework Equations

v=wr

L=Iw

## The Attempt at a Solution

Initially the angular momentum is : 2*1

^{2}*[itex]\frac{4}{1}[/itex] = L = 8

By conservation of angular momentum we should have L = 8 when the string becomes 2m long :

2*2

^{2}*[itex]\frac{v^2}{2}[/itex] = 8 v=2

^{0.5}

Is this correct ?