For a transverse wave on a string the string displacement is described by y(x,t)= f(x-at)where f is a given function and a is a positive constant.Which of the following does NOT necessarily follow from this statement?
A)The shape of the string at time t = 0 is given by f(x).
B)The shape of the waveform does not change as it moves along the string.
C)The waveform moves in the positive x direction.
D)The speed of the waveform is a.
E)The speed of the waveform is x/t.

Question

Quizplus · Accepted Answer

The speed of the waveform is given by the constant $a$, not by $x/t$, which would imply a variable speed depending on position and time. The form $y(x,t) = f(x - at)$ indicates a wave moving in the positive x-direction with a constant speed $a$, preserving its shape.

For a Transverse Wave on a String the String Displacement