A vibrator in a ripple tank vibrates with a frequency of 3.0 Hz and an amplitude of 2.5 cm. The resulting waves travel away from the source with a speed of 2.5 cm/s, passing under various markers floating on the water. (a)In what direction(s) do the marker move?
(b) With what frequency do the marker oscillate?
(c) If the frequency of the source is changed to 4.5 Hz, what will happen to: (i) the speed of the wave?
(ii) the frequency of the marker's oscillations?
(d) If the amplitude of the source is changed to 1.6 cm, what will happen to:
(i) the speed of the wave?
(ii) the frequency of the marker's oscillations?
To answer these questions, we need to understand some basic concepts related to waves, such as frequency, amplitude, and wave speed. Let's go step by step.
(a) In what direction(s) do the marker move?
When a wave passes through a medium like water, the particles of the medium vibrate back and forth perpendicular to the direction of wave motion. In this case, the vibrator in the ripple tank creates waves that travel away from the source. So, the markers floating on the water will also move up and down, perpendicular to the direction of wave motion.
(b) With what frequency do the marker oscillate?
The frequency of the marker's oscillations will be the same as the frequency of the source, which is given as 3.0 Hz.
(c) If the frequency of the source is changed to 4.5 Hz, what will happen to:
(i) the speed of the wave?
The speed of the wave depends on the properties of the medium and is unrelated to the frequency of the source. Therefore, the speed of the wave will remain constant at 2.5 cm/s.
(ii) the frequency of the marker's oscillations?
The frequency of the marker's oscillations will now become 4.5 Hz, matching the new frequency of the source.
(d) If the amplitude of the source is changed to 1.6 cm, what will happen to:
(i) the speed of the wave?
The speed of the wave remains unaffected by the amplitude of the source. Therefore, the speed of the wave will still be 2.5 cm/s.
(ii) the frequency of the marker's oscillations?
The frequency of the marker's oscillations will still be the same as the frequency of the source (either 3.0 Hz or 4.5 Hz, depending on the previous change). The amplitude of the source does not affect the frequency of the marker's oscillations.
In summary:
(a) The marker moves vertically, up and down, perpendicular to the direction of wave motion.
(b) The marker's oscillations have a frequency of 3.0 Hz.
(c) (i) The speed of the wave remains constant.
(ii) The frequency of the marker's oscillations matches the frequency of the source.
(d) (i) The speed of the wave remains constant.
(ii) The frequency of the marker's oscillations remains the same as the frequency of the source.