Consider the glider of Example 7.7 (Section 7.2) and Fig. 7.16. As in the example, the glider is released from rest with the spring stretched 0.100 m. What is the displacement x of the glider from its equilibrium position when its speed is 0.20 m/s? (You should get more than one answer. Explain why.)

Solution 21E Introduction From the stretching of the spring we can calculate the maximum potential energy. Then from the given speed we can calculate the kinetic energy at that point. So we can calculate the potential energy of that point and from the potential energy we can calculate the position of the glider. Step 1 The maximum stretching of the spring is A = 0.100 m. So the maximum potential energy of the glider is Now the kinetic energy at the given point is So the potential energy at that point is So the displacement of the glider is ± 0.092 m.