State how progressive waves and stationary waves differ in whether they transfer energy along the wave.
Use Fig. 4.1 to find the wavelength of the wave.
Calculate the wave speed.
Determine the phase difference for points Q and R.
A progressive wave travels from left to right along a stretched string. Fig. 4.1 shows part of the string at one instant. P, Q and R are three different points on the string. The distance between P and R is $0.48\,\text{m}$. The wave has a period of $0.020\,\text{s}$.
Fig. 4.1 shows the string at time $t = 0$. Describe how the displacement of point Q on the string changes with time from $t = 0$ to $t = 0.010\,\text{s}$.
A stationary wave is produced on another string stretched between fixed points X and Y. Fig. 4.2 shows the string at the instant when every point is at maximum displacement.
Explain what is meant by the term node in a stationary wave.
State how many antinodes are shown by the wave in Fig. 4.2.
State the phase difference between points W and Z along the string.
A new stationary wave is now formed on the string. The new wave has a frequency that is half of the frequency of the wave shown in Fig. 4.2. The speed of the wave is unchanged. On Fig. 4.3, draw a position of the string, for this new wave, when every point is at maximum displacement.