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sergiokapone
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Homework Statement
Rod AB of length [itex]2l[/itex], inclined to the horizontal at an angle [itex]\phi[/itex], falls, without rotating, with some height [itex]h[/itex] on a horizontal table and hits the table surface elastically first left, then right end. During the strike the right end, the rod again consist angle with the horizone [itex]\phi[/itex]. Find the height [itex]h[/itex].
Homework Equations
Energy conservation law [itex]mgh=I_{CM}\dfrac{\omega^2}{2}[/itex] (1)
where [itex]I_{CM}[/itex] - moment of inertia about the center of mass of the rod.
Motion of center mass [itex]m\dfrac{dv_{CM}}{dt}=mg-N[/itex] (2)
where [itex]N[/itex] - normal reaction, acting on the left edge of the rod.
Rotational motion [itex]I_{CM}\dfrac{d\omega}{dt}=N l cos \phi[/itex] (3)
The Attempt at a Solution
And now no idea, how to solve.
Of course, the height can be found from the law of conservation of energy. In an elastic collision, the kinetic energy of translational motion partially transferred to the rotational kinetic energy, and the center of mass is not raised at the previous height, but on the other, where the selected zero potential energy. Therefore, in (1) [itex]\omega[/itex]- the final angular velocity, I do not know how to find.
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