Distinguish between free oscillations and forced oscillations.
A trolley is supported on a horizontal surface by two stretched springs, as illustrated in Fig. 4.1. One spring is fixed to a stationary point. The other spring is connected to an oscillator that makes the trolley oscillate horizontally. The oscillator vibrates with a constant vibration amplitude. Its vibration frequency is then increased gradually from a very low value. Fig. 4.2 shows how the trolley’s vibration amplitude $x_0$ varies with frequency $f$.
Use Fig. 4.2 to state and explain the value of the natural frequency of vibration of the trolley.
Use Fig. 4.2 to state and explain whether there are any frictional forces acting on the trolley.
The oscillator in (b) is now switched off. The trolley is displaced horizontally by $4.7\,$cm along the line of the springs. It is then released. Use information from Fig. 4.2 to estimate the trolley’s maximum speed.