Seismometers are used to detect and measure the shock waves that travel through the Earth due to earthquakes.

This diagram shows the structure of a simple seismometer. The shock wave will cause the mass to vibrate, causing a trace to be drawn on the paper scroll.

The frequency of a typical shock wave is between $30$ and $40 Hz$. Explain why the natural frequency of the spring- mass system in the seismometer should be very much less than this range of frequencies. This graph shows the acceleration of the mass against its displacement when the seismometer is recording an earthquake.

Seismometers are used to detect and measure the shock waves that travel through the Earth due to earthquakes. This diagram shows the structure of a simple seismometer. The shock wave will cause the mass to vibrate, causing a trace to be drawn on the paper scroll.

The graph in figure shows the acceleration of the mass against its displacement when the seismometer is recording an earthquake.

What evidence does the graph give that the motion is simply harmonic ?

Seismometers are used to detect and measure the shock waves that travel through the Earth due to earthquakes.

This diagram shows the structure of a simple seismometer. The shock wave will cause the mass to vibrate, causing a trace to be drawn on the paper scroll.

The graph in figure shows the acceleration of the mass against its displacement when the seismometer is recording an earthquake.

Use information from the graph to calculate the frequency of the oscillation.