Question

A triangle pulse moving at 2 cm/s on a rope approaches an end at which it is free to slide on a vertical pole.

(a) Draw the pulse at 1/2 s interval unit it is completely reflected.

(b) What is the particle speed on the trailing edge at the instant depicted ?

Answer 1

(a) Reflection of a pulse from a free boundary is really the superposition of two identical waves travelling in opposite direction. This can be shown as under.

In every 1/2 s, each pulse (one real moving towards right and one imaginary moving towards left) travels a distance of 1 cm, as the the wave speed is 2 cm/s.