Lagrange Multipliers: Force of Constraint for a Yo-Yo

A disk has a string wrapped around it and is released from rest. What is the tension in the string?

Second Semester Classical Mechanics Playlist

[marcrindermann]

12:54 is there a reason you didn't substitute I / R² with 1/2 m? After all, you wrote down earlier that I = 1/2 m R².

λ = 1/3 m g would have been much nicer than the expression you had on paper.

[fizixx]

I like the two different approaches. Funny that the classical method is easier for this problem, but that's how it is with more powerful techniques.