a cube of mass m sliding without frictionat speed v0. It undergoes a perfectly elastic collision with the bottom tip of a rod of length d and mass M = 2m. The rod is pivoted about a frictionless axle through its center, and initially it hangs straight down and is at rest. What is the cube's velocity - both speed and direction - after the collision?

Respuesta :

The cube's velocity - both speed and direction - after the collision is  [tex]v=\frac{v_0}{5}[/tex].

What is kinetic energy conservation?

Kinetic energy, which may be seen in the movement of an object, particle, or group of particles, is the energy of motion. Any moving item uses kinetic energy, such as a person walking, a baseball being thrown, a piece of food falling off a table, or a charged particle in an electric field.

From kinetic energy conservation:

[tex]\begin{gathered}\frac{m v_0^2}{2}=\frac{m v^2}{2}+\frac{I \omega^2}{2} \\I=\frac{M d^2}{12}=\frac{2 m d^2}{12}=\frac{m d^2}{6} \\\frac{m v_0^2}{2}=\frac{m v^2}{2}+\frac{m d^2 \omega^2}{12} \\v_0^2=v^2+\frac{d^2 \omega^2}{6} \Longrightarrow(1)\end{gathered}[/tex]

From angular momentum conservation:

[tex]\begin{gathered}\frac{m v d}{2}=I \omega \\\frac{m v_0 d}{2}=\frac{m d^2 \omega}{6} \\v_0=\frac{d \omega}{3} \\d^2 \omega^2=9 v_0^2 \Longrightarrow(2)\end{gathered}[/tex]

Substituting (2) into (1):

[tex]\begin{gathered}v^2=v_0^2-\frac{3 v_0^2}{2} \\v^2=-\frac{v_0^2}{2}\end{gathered}[/tex]

The correct answer is: [tex]v=\frac{v_0}{5}[/tex]

To learn more about kinetic energy conservation visit:https://brainly.com/question/13323489

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