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Question
Displacement versus time curve for a particle executing S.H.M. is shown in figure. Identify the points marked at which (i) velocity of the oscillator is zero, (ii) speed of the oscillator is maximum.

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Solution
In SHM y-t graph, zero displacement values correspond to the mean position; where the velocity of the oscillator is maximum.
Whereas the crest and troughs represent extreme positions, where displacement is maximum and velocity of the oscillator is minimum and is zero. Hence,
- A, C, E and G are either crests or trough having zero velocity.
- Speed is maximum at mean positions represented by B, D, F, and H paints.
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