A simple pendulum as shown in Fig. 4.24 oscillates back and forth. Use the letter designations in the figure to identify the pendulums position(s) for the following conditions. (There may be more than one answer. Consider the pendulum to be ideal with no energy losses.) (a) Position(s) of instantaneous rest ___ (b) Position(s) of maximum velocity ___ (c) Position(s) of maximum Ek ___ (d) Position(s) of maximum Ep ___ (e) Position(s) of minimum Ek ___ (f) Position(s) of minimum Ep ___ (g) Position(s) after which Ek increases ___ (h) Position(s) after which Ep increases ___ (i) Position(s) after which Ek decreases ___ (j) Position(s) after which Ep decreases ___ Figure 4.24 The Simple Pendulum and Energy

Consider a block of mass 0.200 kg attached to a spring of spring constant 100 N/m. The block is placed on a frictionless table, and the other end of the spring is attached to the wall so that the spring is level with the table. The block is then pushed in so that the spring is compressed by 10.0 cm. Find the speed of the block as it crosses (a) the point when the spring is not stretched, (b) 5.00 cm to the left of point in (a), and (c) 5.00 cm to the right of point in (a).

Check Your Understanding Suppose the mass in Equation 8.6 is doubled while keeping the all other conditions the same. Would the maximum expansion of the spring increase, decrease, or remain the same? Would the speed at point B be larger, smaller, or the same compared to the original mass?