# The sound of steel rods

Classical Mechanics Level 4

Two thin and identical steel rods move with equal speeds $$v= 1 ~\mbox{m/s}$$ in opposite directions and collide longitudinally. The collision is perfectly elastic and the rods swap their velocities. How long does the collision last in seconds if the length of the rods is $$l=30~\mbox{cm}$$. Assume that the speed of sound in the steel rods is $$c=5000 ~\mbox{m/s}$$.

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