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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Momentum

Mass times velocity, p=mvp = mv, in kg m/s. It sets the de Broglie wavelength (λ=h/p\lambda = h/p), and its uncertainty is limited by the uncertainty principle (Δx Δp≥h/4π\Delta x\,\Delta p \ge h/4\pi).

Example

An electron at 1.00×1061.00\times10^{6} m/s has p=9.11×10−25p = 9.11\times10^{-25} kg m/s; a 0.145 kg baseball at 40.0 m/s has p=5.80p = 5.80 kg m/s, so its wavelength is over 102410^{24} times shorter.

See alsode Broglie wavelengthHeisenberg uncertainty principle