2ElasticityWhen you hang a weight on a spring, the weight applies a force to the spring and it stretches in direct proportion to the applied force.According to Hooke’s law, the amount of stretch (or compression), x, is directly proportional to the applied force F.Double the force and you double the stretch; triple the force and you get three times the stretch, and so on: F ~ ∆x
3ElasticityIf an elastic material is stretched or compressed more than a certain amount, it will not return to its original state.The distance at which permanent distortion occurs is called the elastic limit.Hooke’s law holds only as long as the force does not stretch or compress the material beyond its elastic limit.
16Longitudinal WavesWave motion is parallel to equilibrium
17Wave Properties Pulse wave Reflection A wave that is just one interference – no repetitionReflection
18Constructive and Destructive Interference Constructive interferenceA superposition of two or more waves in which individual displacements on the same side of the equilibrium position are added together to form the resultant wave
19Constructive and Destructive Interference A superposition of two or more waves in which individual displacements on opposite sides of the equilibrium position are added together to form the resultant wave
20speed of a wave = (frequency) (wavelength) v = f λ 1. A piano emits frequencies that range from a low of about 28 Hz to a high of about 4200 Hz. Find the range of wavelengths in air attained by this instrument when the speed of sound in air is 340 m/s.2. The red light emitted by a He-Ne laser has a wavelength of 633 nm in air and travels at the speed of light (3.00 x 108 m/s). Find the frequency of the laser light.
21De Broglie WavesLouis de Broglie suggested that all matter has wavelike characteristics.where h is Planck’s constant, equal to 6.63 x J·s.This wavelength is too small to notice interference for large objects. This idea becomes important when looking all things at the microscopic level.
22De Broglie WavesWhat is the wavelength of an electron (mass = 9.11 x 10¯31 kg) traveling at 5.31 x 106 m/s?