Page 3 - Vibrations
P. 3
Vibrations are around us
Nature of sound
Consider a horizontal
tube of air.
Partition the air into
regions as shown on
the left.
All is quite at t 0.
In t 1 region 1 expands
to a volume as shown
in red.
This causes the region 2
to become compressed
shown in blue.
In t 2 region 1 has
recovered and region 2 has expanded (reacting to being
rd
compressed – Newton 3 Law) and region 3 has now been
compressed.
In t 3 Regions 2 has recovered, region 3 has expanded and
region 4 has been compressed.
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