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?

Question

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

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Answer 1 · 2018-03-07T07:10:30

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#