A metronome is used by musicians to make regularly spaced ticking sounds, to help maintain rhythm. You are designing a metronome that consists of a simple freely- hanging pendulum that swings back and forth, making ping' sound at the top of each swing. If you want the metronome to make 160 pings per minute, how long should the pendulum be? Hint: During each full oscillation, the pendulum will make two pings. [Note for the musicians out there: real metronomes use an inverted pendulum with multiple masses on them to achieve a broader range of frequencies. We are considering a simpler system here.] A. 0.76 cm B. 1.2 cm C. 3.5 cm D. 14 cm E. 120 cm