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A uniform stick 1.0 m long with a total mass of 270 g is pivoted at its center. A 3.0 g bullet is shot through the stick midway between the pivot and one end. The bullet approaches at 250 m/s and leaves at 140 m/s. With what angular speed is the stick spinning after the collision

Respuesta :

Answer:

3.67 rad/s

Explanation:

L = Length of meter stick = 1 m

r = Distance at which the bullet will hit the stick = [tex]\frac{L}{4}=\frac{1}{4}[/tex]

m = Mass of bullet = 3 g

M = Mass of stick = 270 g

[tex]v_1[/tex] = Velocity of bullet = 250 m/s

[tex]v_2[/tex] = Velocity of bullet leaving = 140 m/s

Initial angular momentum

[tex]L_i=mv_1r[/tex]

Final angular momentum of the system

[tex]L_f=\frac{1}{12}ML^2\omega+mv_2r[/tex]

Since, angular momentum is conserved we have

[tex]mv_1r=\frac{1}{12}ML^2\omega+mv_2r\\\Rightarrow \omega=\frac{12(mv_1r-mv_2r)}{ML^2}\\\Rightarrow \omega=\frac{12(0.003\times 250\times \frac{1}{4}-0.003\times 140\times \frac{1}{4})}{0.27\times 1^2}\\\Rightarrow \omega=3.67\ rad/s[/tex]

The angular speed is the stick spinning after the collision is 3.67 rad/s