Answer: Both. But for O-level Physics, you can safely assume that sound is transmitted as a longitudinal wave in solid, liquid or gas.
According to Physics Matters GEO 'O' Level Physics (4th edition) by C. Chew, S.F. Chow and B.T. Ho:
Sound waves travel parallel to the direction of vibration of a medium, and hence are longitudinal waves.
But according to University Physics with Modern Physics (6th edition) by H. Young and R. Freedman:
Sound waves in fluids are longitudinal.
Longitudinal waves depend on the compressibility of the fluid for their propagation. Transverse waves require a restoring force in response to sheer strain. Fluids do not have the underlying structure to supply such a force. A fluid cannot support static sheer. A viscous fluid can temporarily be put under sheer, but the higher its viscosity the more quickly it converts input work into internal energy. A local vibration imposed on it is strongly damped, and not a source of wave propagation.
0 comments:
Post a Comment