Tacoma Narrows Bridge (1940) Billah and Scanlan (1991) reported that in fact, many physics textbooks (for example Resnick et al. and Tipler et al.) wrongly explain that the cause of the failure of the Tacoma Narrows bridge was externally forced mechanical resonance. Resonance is the tendency of a system to oscillate at larger amplitudes at certain frequencies, known as the system's natural frequencies. At these frequencies, even relatively small periodic driving forces can produce large amplitude vibrations, because the system stores energy. For example, a child using a swing realizes that if the pushes are properly timed, the swing can move with a very
Scattering amplitude quantum mechanical approach is given by the S matrix formalism. The scattering amplitude can be determined by the scattering length in the low-energy regime. Scattering amplitude In quantum physics, the scattering amplitude is the probability amplitude of the outgoing spherical wave relative to the incoming plane wave in a stationary-state scattering process. The latter is described by the wavefunction where formula_2 is the position vector; formula_3; formula_4 is the incoming plane wave with the wavenumber along the axis; formula_5 is the outgoing spherical wave; is the scattering angle; and formula_6 is the scattering amplitude. The dimension of the scattering amplitude