A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure (15-E12). The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the support is pushed to the right by 10 cm so that the joint is placed on the pulley, what will be the minimum frequency at which the heavy string can resonate?
As per the question, the end A is free so, antinode must be formed there.
In case of one free end, it is open to air, so air pressure must be present on that end and now,
pressure and displacement are out of phase, so it creates an antinode.
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Now the movable support is pushed to the right by 10 m, so that the joint is placed on the
pulley, and a node will be formed there.
Tension and velocity remains same.
As wavelength reduces, frequency increases.
So, 