- #1
bhimberg
- 20
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Homework Statement
A spool with radius r and mass M sits upright on a table, a distance l from the edge. The string hangs off the edge of the table with a mass m attached. The table is frictionless: what will the velocity of the weight be when the spools center of mass reaches the edge of the table (l is measured from the spools center of mass to the edge).
Homework Equations
(Torque)=I(alpha)
I(alpha)=.5(M^2)(theta'')=F x r = F*r*sin(angle between F and r)
r(theta'')+x''=y'', where x is at the com of the spool and y is the com of the weight
what I'm having trouble with is the tension. The F in the torque equation should be the tension on M at r due to m. I've written down the equation:
my''=mg-T, where T is Mx''.
The thing is, the tension should be at its maximum when M (or Mx'') is stationary. The above equation has tension at 0 at that point. Perhaps I'm confusing total tension with the the force applied due to tension?