compression

Examples of compression in the following topics:

• Longitudinal Waves

  • Longitudinal waves, sometimes called compression waves, oscillate in the direction of propagation.
  • A sound wave contains pulses, which are the products of compressing the air (or other media) particles.
  • Some longitudinal waves are also called compressional waves or compression waves.
  • Sound waves are created by the compression of a medium, usually air.
  • A compressed Slinky is an example of a longitudinal wave.

• Stress and Strain

  • Deformations come in several types: changes in length (tension and compression), sideways shear (stress), and changes in volume.
  • (b) Compression: The same rod is compressed by forces with the same magnitude in the opposite direction.
  • For very small deformations and uniform materials, $\Delta L$ is approximately the same for the same magnitude of tension or compression.
  • For larger deformations, the cross-sectional area changes as the rod is compressed or stretched.

• Elasticity, Stress, and Strain

  • (b) Compression: The same rod is compressed by forces with the same magnitude in the opposite direction.
  • For very small deformations and uniform materials, ΔL is approximately the same for the same magnitude of tension or compression.
  • For larger deformations, the cross-sectional area changes as the rod is compressed or stretched.

• Speed of Sound

  • There are two different kinds of sound waves: compression waves and shear waves.
  • Compression waves can travel through any media, but shear waves can only travel through solids.
  • The speed of a compression wave is determined by the media's compression capacity, shear modulus, and density, while the speed of the shear wave is only determined by the shear modulus and density.

• Application of Bernoulli's Equation: Pressure and Speed

  • The Bernoulli equation can be adapted to flows that are both unsteady and compressible.
  • However, the assumption of inviscid flow remains in both the unsteady and compressible versions of the equation.
  • Compressibility effects depend on the speed of the flow relative to the speed of sound in the fluid.
  • Adapt Bernoulli's equation for flows that are either unsteady or compressible

• Springs

  • When a spring is stretched/compressed from its equilibrium position by x, its potential energy is give as $U = \frac{1}{2} kx^2$.
  • The displacement x is usually measured from the position of "neutral length" or "relaxed length" - the length of spring corresponding to situation when spring is neither stretched nor compressed.
  • Red is used extension, blue for compression.

• Fracture

  • Bones, on the whole, do not fracture due to tension or compression.
  • The behavior of bones under tension and compression is important because it determines the load the bones can carry.
  • Overweight people have a tendency toward bone damage due to sustained compressions in bone joints and tendons.

• Characteristics of Sound

  • Sound is a longitudinal wave of pressure that travels through compressible medias, which can be solid, liquid, gaseous, or made of plasma.
  • Sound is a wave—a longitudinal wave of pressure that travels through compressible medias (i.e., solid, liquid, gaseous, or made of plasma).

• What is a Fluid?

  • Solids can be subjected to shear stresses, and normal stresses—both compressive and tensile.
  • In contrast, ideal fluids can only be subjected to normal, compressive stress (called pressure).

• Introduction to Two Coupled Masses

  • And the force each of these springs transmits is governed by the extent to which the spring is compressed or extended.
  • Referring to Figure 1.10, spring 1 can only be compressed or extended if mass 1 is displaced from its equilibrium.
  • Now, spring 2 is compressed or stretched depending on whether $x_1 - x_2$ is positive or not.
  • Then spring 2 is compressed relative to its equilibrium length and the force on mass 1 will in the negative $x$ direction so as to restore the mass to its equilibrium position.