Draw a graph between displacement from mean position and time for a body executing free vibrations in vacuum.

State one way of increasing the frequency of a note produced by an air column.

The digram below in fig. 7.11 shows three ways in which the string of length l in an instrument can vibrate.

(a) Which of the diagram shows the principal note?

The digram below in fig. 7.11 shows three ways in which the string of length l in an instrument can vibrate.

(b) Which has the frequency four times that of the first?

The digram below in fig. 7.11 shows three ways in which the string of length l in an instrument can vibrate.

(c) Which vibration is of the longest wavelength?