- #1
Ocsycleen
- 10
- 1
Homework Statement
A 4 g bullet traveling at 500 m/s strikes a disk of mass 1 kg and
radius 10 cm that is free to rotate around an axis passing through its
center. The bullet’s incoming path is 5 cm above the rotation axis and
the bullet comes to rest in the position shown in the figure. At how
many revolutions per second is the disk is rotating afterwards?
(Ignore the mass of the bullet after it hits the disk.)
https://gyazo.com/7ba8193726c76f57aa6c3ffa9e0c2930
the answer is 3.18 but i can't seem to figure out how to do this.
Homework Equations
L(initial) = L (final)
LDisk = 1/2MR^2[/B]
The Attempt at a Solution
[/B]
Here is what i got so far using conservation of angular momentum
R* Mass of Bullet * Velocity of bullet * sin([PLAIN]http://physics-help.info/physicsguide/appendices/si_units_images/image002.gif[/I]) = IDisk * ωFinal
0.1m * (0.004kg)(500)sin([PLAIN]http://physics-help.info/physicsguide/appendices/si_units_images/image002.gif) = (1/2) (1kg) (0.1)^2 * ωFinal
But i can't seem to figure what the theta is in this case and how to incorporate 5cm above the rotation axis into the problem.
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