hi, im having a little trouble with the last part of this problem.(adsbygoogle = window.adsbygoogle || []).push({});

A particle of mass m is moving on a frictionless horizontal table and is attached to a massless string, whose other end passes through a hole in the table, where i am holding it. Initially the particle is moving in a circle of radius R_0 with angular velocity w_0, but i now pull the string down through the hole until length R remains between the whole and the particle. (a) whats the particles angular velocity now? (b) assuming that I pull the string slowly that we can approximate the particles path by a circle of slowly shrinking radius, calculate the work i did pulling the string.

i was able to get part a by using conservation of angular momentum and i got

w= (R_0/R)^2*w_0

for part b i know that to find the work done i need to take the integral of F.dr, but i and not really sure how i would set that up.

thanks

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