A projectile of mass m is traveling at a constant velocity v0, toward a stationa
ID: 2181381 • Letter: A
Question
A projectile of mass m is traveling at a constant velocity v0, toward a stationary disk (I = MR2/2) that is free to rotate about a pivot through its center axis O. Before impact, the projectile is traveling along a line displaced a distance b below the axis. The projectile sticks to the disk at point B. (a.) Before impact, what is the angular momentum of the system about the O axis? (b.) After impact, what is the angular velocity ? of the projectile-and-disk system?
I need an explanation in the simplest possible terms; explaing what each variable in the equations used represents.
Explanation / Answer
Lo=initial angular momentum of the system about O= angular momentum of projectile
Lo= mvob
AS there is no external torque about O, angular momentum of the system about O remains conserved.
Lo=Lf
Lf=I+mb2=mvob
=mvob/(I+mb2)= mvob/(0.5MR2+mb2)
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