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Quantum Pin Ball

In this problem you will investigate the feasibility of quantum uncertainty effects playing a role in a simplified version of Pin Ball.

In this version of Pin Ball, the table is flat so that gravity plays no role, and there is a series of small pins (of radius ) at an average spacing of D=10cm. The object is to hit a small ball (mass m=10 g, radius small enough to ignore) at a horizontal velocity () horizontally (along ) at just the right angle and height y so that it collides with a predetermined series of pins and eventually enters the goal. (See figure below.) You will show that after a relatively small number of pins, even under idea circumstances, it is impossible to do this on a regular basis. Such regular behavior is forbidden by the Heisenberg Uncertainty Principle (HUP) of quantum mechanics.



Prof. Tomas Alberto Arias
Mon Feb 26 15:11:01 EST 1996