Video Transcript
A transverse wave is shown in the
diagram. What is the amplitude of the
wave?
To begin, we should recall that the
amplitude of a wave is defined as the maximum displacement of the oscillating medium
that the wave travels in. This oscillation is shown in the
diagram. It’s a graph of displacement as a
function of time. Notice the sinusoidal shape that’s
indicative of transverse waves. The oscillations are centered
around the horizontal axis of the graph. So a displacement of zero marks the
wave’s equilibrium position. This is the baseline for measuring
the displacement of the wave.
In this question, we want to find
its maximum displacement or amplitude, which the medium reaches every time there’s a
crest or trough in the waveform. We can see that there’s an equal
amount of displacement in the positive and negative directions. But for easier reading on the
vertical axis, let’s just focus on this first crest here. We know that it occurs at a time of
one second. And to find the displacement at
this moment, we trace the height of the crest directly over to the vertical
axis.
Using this dashed horizontal line
to help us take the proper reading from the scale, we can see that the crest is two
of these small gray marks above 1.5 meters. Notice that five of these small
gray marks occur over a range of 0.5 meters. Therefore, each of these small gray
marks represents a tenth of a meter. This means that the amplitude of
the wave spans one and a half meters plus two-tenths of a meter for a total of 1.7
meters. Thus, the amplitude of the
transverse wave shown in the diagram is 1.7 meters.
