A transverse wave is traelling along a string from left to right. The fig. represents the shape of the string (snap-shot) at a given instant. At this instant

(A) Which points have an upward velocity , (B) which points have downward velocity
(C) which point have zero velocity , (D) which point have maximum magnitude of velocity.

Answer

(a) `D, E, F` , (b) `A, B, H` , (c) `C, G` , (d) `A, E`

Explanation

(a) `D, E, F rArr` (slope `= -ve rArr v_(p) = +ve`)
(b) `A, B, H rArr` (slope `= +ve rArr v_(p) = -ve`)
(c) At `C, G`, [slope `=0`]
(d) At `A, E` [slope is maximum]