State the meaning of resonance.
A small ball is supported by a stretched string. One end of the string is fixed to a wall, while the other end is attached to a vibration generator, as shown in Fig. 4.1. At the start, the vibration generator is switched off. A student moves the ball vertically and then lets it go. Fig. 4.2 shows how the displacement of the ball varies with time after release.
State the name of the phenomenon shown by the reduction in the amplitude of the oscillations in Fig. 4.2.
Explain the decrease with time of the amplitude of the ball’s oscillations.
Determine the frequency of the ball’s oscillations.
The vibration generator in (b) is switched on and its frequency $f$ of vibration is gradually increased from $0$ to $10\,\text{Hz}$. On Fig. 4.3, sketch how the amplitude of the oscillations of the ball changes with $f$.