A block with mass M rests on a frictionless surface and is connected to a horizontal spring of force constant k. The other end of the spring is attached to a wall (Figure 1). A second block with mass m rests on top of the first block. The coefficient of static friction between the blocks is ?_s.

Find the maximum amplitude of oscillation such that the top block will not slip on the bottom block. Express your answer in terms of the variables m, M, k, ?_s, and appropriate constants.

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