The graph shows a rover's position. What is the rover's position, in m, at t = 6 s?
Ripples cross a wave tank, crest after crest sliding toward the far wall while the surface rises and falls. A sensor catches the whole tank at one instant, and Dilys gets the printed picture with two questions: how big, and how long?
The ripples themselves come first. The snapshot drawing from earlier lessons then gets axes and gridlines: it becomes a graph, and the two size numbers read straight off it.
Watch the tank first. The water's surface rises and falls, and the pattern of crests slides steadily along: that moving water is the thing being measured.
The sensor's picture holds the whole tank at one instant: every position along the tank, and how far the surface sits from rest at each one.
Drawn with axes, the picture becomes a displacement-position graph: position along the tank, in m, runs across; displacement of the surface, in cm, runs up.
Use the gridlines: run from a crest top across to the displacement axis for the amplitude; run down from two successive crest tops and subtract for the wavelength.
Troughs work too: a trough's displacement sits at minus one amplitude, and trough to next trough spans one wavelength.
A displacement-position graph of a tank wave shows crest tops at displacement 4 cm, with one crest at position 0.5 m and the next at position 2.5 m. Read the amplitude and the wavelength.
Amplitude: the crest top sits at 4 cm on the displacement axis, so the amplitude is 4 cm.
Wavelength: successive crests sit at 0.5 m and 2.5 m.
2.5 - 0.5 = 2
Amplitude 4 cm; wavelength 2 m.
The graph shows one instant of a wave running along a pool's lane rope. Enter the wave's amplitude in cm.
The graph shows one instant of a rope wave. Successive crests sit at the positions marked by the read guides. Enter the wavelength in m.
Anselm reads a displacement-position graph and says: 'The position distance from one trough's lowest point to the next trough's lowest point on this graph is one wavelength.' Is Anselm correct?
The graph shows one instant of ripples in a testing flume. Enter the ripples' amplitude in cm.
The graph shows one instant of a wave in a harbor model. Successive crests sit at the positions marked by the read guides. Enter the wavelength in m.
Which procedure gives a wave's wavelength from a displacement-position graph?