State what damping means.
State the evidence in Fig. 4.2 that the ball's motion is damped.
The acceleration $a$ of the ball and its displacement $x$ are connected by $a = -\left(\frac{2k}{M}\right)x$, where $k$ is the spring constant of one spring. The mass $M$ of the ball is $1.2\,\text{kg}$. Use information from Fig. 4.2 to determine the angular frequency $\omega$ of the ball's oscillations.
Use your answer in (i) to find the value of $k$.
The oscillator is now switched on. Its amplitude of oscillation remains constant. The angular frequency of the oscillations is then increased gradually from $0.7\omega$ to $1.3\omega$, where $\omega$ is the angular frequency found in (b)(i). On the axes in Fig. 4.3, show how the amplitude $A$ of the ball's oscillation varies with angular frequency.
Some sand is now spread on the horizontal surface. The angular frequency of the oscillations is again increased gradually from $0.7\omega$ to $1.3\omega$. State two changes that happen to the line you have drawn on Fig. 4.3.