The moment of inertia of the rod rotating about its center is M*L^2/12
When the idential masses m are at radius R, the moment of intertia due to their masses is 2*m*R^2
The total angular momentum remains unchanged. Let w1 be the initial angular velocity.
A) When the masses move half way to the ends of the rod, their radius is R = L/4. The angular velocity becomes a new value w2. You can solve for it using the momentum conservation equation.
(ML^2/12)*w1 = [(ML^2/12)+2*m*(L/4)^2
]*w2
B) Use the formula for kinetic energy, (1/2)I*w^2, and compare the before and after values.
C) Repeat A), but with R = L/2 instead of L/4.
A long thin rod of mass M=2.00 kg and length L=75.0 cm is free to rotate about its center. Two identical masses (each of mass m = .45kg) slide without friction along the rod. The two masses begin at the rod's point of rotation when the rod is rotating at 10.0 rad/s.
A) When they have moved halfway to the end of the rod, how fast (rad/s) is the rod rotating?
B) When the masses are halfway to the end of the rod, what is the ratio of the final kinetic energy to the initial kinetic energy (Kf/Ki)?
C) When they reach the end, how fast is the rod rotating (rad/s)?
3 answers
Thank you so much!
Hi Miki! I think we are taking the same physics class...
I'd like to possibly share insights about the material and possibly help each other out in a mutually beneficial way. If you are interested, shoot me an email at William dot Cordoba at yaho dot com
Thanks
William
I'd like to possibly share insights about the material and possibly help each other out in a mutually beneficial way. If you are interested, shoot me an email at William dot Cordoba at yaho dot com
Thanks
William