A
Level Physics Notes: Waves and Oscillations – The Sonic Boom
When an object travels faster than the speed of sound in a fluid,
it generates a shock wave. The shock wave forms a cone from the front
of the object and spreads out to form a trailing cone, as shown below
for a supersonic plane.
The shock wave travels at the speed of sound – about
or
at
sea level at a temperature of 20 degrees celsius. The speed of sound
is labelled Mach 1. The half angle
between
the line of flight of the object and the shock wave is given by
- The fast the
object, the more point the cone.
-
In fact two booms are experienced by observers. One as they enter
the cone and one as they leave it.
-
A may generate a small sonic boom. A bullwhip tapers down from the
handle section to the end, which is much lighter than the handle.
When the whip is swung, energy is transferred down the length of the
tapering whip. In accordance with the formula (if the work for
whipping remains constant) for kinetic energy
the
velocity of the whip increases with the decrease in mass,so if the
whip is swung fast enough, a sonic boom may be generated.