When a 0.20-kg block is suspended from a vertically hanging spring, it stretches the spring from its original length of 0.050 m to 0.060 m. The same block is attached to the same spring and placed on a horizontal, frictionless surface. 0.20 kg www The block is then pulled so that the spring stretches to a total length of O.10 m. The block is released at time t = 0 and undergoes simple harmonic motion. Which one of the following statements is true concerning the motion of the block? O Its acceleration is greatest when the spring returns to the 5.0 cm position. O Its acceleration is greatest when the mass has reached its maximum displacement. O Its velocity is greatest when the mass has reached its maximum displacement. O Its acceleration is constant.

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Problem 4: Speed deamplifier. In the figure above on the right, block 1 of mass m1 slides along an x-axis on a frictionless floor at speed 4 m/sec.Then it undergoes a one-dimensional elastic collision with stationary block 2 of mass m2 = 2m1. Next, block 2 undergoes a one-dimensional elastic collision with stationary block 3 of mass mz = 4m1. What then is the speed of block 3? Answer: 16 m/sec or 1.78 m/sec.