sound question

[kriptik]

need help on this question

[fady_22]

You would have a cos curve, with maximum negative pressure at A, and at 1.8m, and maximum positive pressure (the dark region) at 0.09 m.

[supernatural]

There we go


WORKING OUT
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We can clearly see there is a compression at point X. This means on the graph it will correspond to a point of maximum pressure.

The particles seem spaced out the most at point B. This is an indication to a rarefaction so we will have minimum pressure on the graph.

See at point A and point Y the spacing between the particles (ie pressure) are roughly the same? Therefore on the graph A and Y they will share the same y value.
It seems as though the spacing at A and Y is average (ie room pressure). On the graph we will have x-intercepts at point A and Y.

Now join the dots