- #1
cacofolius
- 30
- 0
Homework Statement
A disk rotates with angular velocity w. Two masses, Ma and Mb, slide without friction in a groove passing through the cnter of the disk. They are connected by a light string of length L, and are initially held in position by a catch, with mass Ma at distance Ra from the center. Neglect gravity. At t=0 the catch is removed and the masses are free to slide. Find r''_a immediately after the catch is removed in terms of Ma, Mb, L, Ra, and w.
Homework Equations
a=(r''-rw^2)êr + (rθ''+2r'we) êθ
The Attempt at a Solution
I figured that immediately after the catch is removed Ma only experiences a centripetal tension that must be equal to the one Mb is experiencing. So we'll have
Mb*r''_b=Ma*r''_a
Mb*r''_b=Mb*(w^2*Rb) = Mb*w^2*(L-Ra)
Ma*r''_a = Mb*w^2*(L-Ra) → r''_a= w^2*(L-Ra)*(Mb/Ma)
I would like to know if this is correct, or if I'm missing something (or everything!).