A wave of period 5.0 ms travels through a medium. The graph shows the variation with distance d of the displacement x of points in the medium. What is the average speed of a point in the medium during one full oscillation?

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a) 0m/s
b) 4m/s
c)16m/s
d) 400m/s
The answer is C, but why is it not D?

1 Answer
Mar 7, 2018

The point moves from -2 cm to +2 cm and then back to -2 cm (for example) in one oscillation, a total distance of 8 cm or 0.08 m.

The period is 5.0 ms = 5.0xx10^-3 s

The average speed is just v_(av)=d/t=0.08/(5xx10^-3)=16 ms^-1