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Homework Statement
A block of mass m slides down a frictionless ramp from height h above the floor. At the base of the ramp it collides and sticks to the lower end of a uniform rod, length L, mass 2m, that is suspended about a pivot at point O, about which it is free to rotate. Express answers in terms of m, g, h, and L.
Find the angle θ through which the system rotates before momentarily coming to rest after the collision.
Homework Equations
I used conservation of energy to determine angular speed ω immediately after collision: Ei = Ef
I used v = Rω to find kinetic energy of the system after collision.
The Attempt at a Solution
I found ω to be √6gh/5L^2 ; I found kinetic energy after the collision to be (9/5)(mgh). However, I'm at a loss at how to find the angle θ. I tried using conservation of angular momentum but became confused - if the initial point is immediately after collision and the final point is when the system is momentarily at rest, that means Li = 0. There has to be a mistake in my reasoning somewhere; I need help bridging this gap I have in my angular knowledge.