(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A yo-yo is made from two uniform disks of raduis R with a combined mass of m. A short massless shaft of radius r connects the disks. A long thin string is wrapped around the shaft several times by a yo-yo player, who releases it with zero speed. Assuming that the string is vertical at all times, find the tension in the string during the descent and subsequent ascent of the yo-yo.

2. Relevant equations

moment of inertia of the yoyo is mR^{2}/2

3. The attempt at a solution

Another one of my exam questions.

Let tension in string be T.

Tr=(mR^{2}/2)(a/r)

mg-T=ma

Solving the 2 equations, I get T=(mR^{2}g/(R^{2}+2r^{2})

For ascent, T-mg=ma

Solving the equations again, I get T=(mR^{2}g/(R^{2}-2r^{2})

Would like to know if this is the correct way to do this

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# Homework Help: Rotational motion of a yo-yo

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