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chronorec
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Homework Statement
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.
Homework Equations
moment of inertia of the yoyo is mR2/2
The Attempt at a Solution
Another one of my exam questions.
Let tension in string be T.
Tr=(mR2/2)(a/r)
mg-T=ma
Solving the 2 equations, I get T=(mR2g/(R2+2r2)
For ascent, T-mg=ma
Solving the equations again, I get T=(mR2g/(R2-2r2)
Would like to know if this is the correct way to do this