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  2. Archimedes' principle - Wikipedia

    en.wikipedia.org/wiki/Archimedes'_principle

    The net force on the object must be zero if it is to be a situation of fluid statics such that Archimedes principle is applicable, and is thus the sum of the buoyancy force and the object's weight F net = 0 = m g − ρ f V disp g {\displaystyle F_{\text{net}}=0=mg-\rho _{f}V_{\text{disp}}g\,}

  3. Hurdle model - Wikipedia

    en.wikipedia.org/wiki/Hurdle_model

    A hurdle model is a class of statistical models where a random variable is modelled using two parts, the first of which is the probability of attaining the value 0, and the second part models the probability of the non-zero values. The use of hurdle models is often motivated by an excess of zeroes in the data that is not sufficiently accounted ...

  4. Arrhenius equation - Wikipedia

    en.wikipedia.org/wiki/Arrhenius_equation

    In physical chemistry, the Arrhenius equation is a formula for the temperature dependence of reaction rates.The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that the Van 't Hoff equation for the temperature dependence of equilibrium constants suggests such a formula for the rates of both forward and ...

  5. Zero-inflated model - Wikipedia

    en.wikipedia.org/wiki/Zero-inflated_model

    Data with such an excess of zero counts are described as Zero-inflated. [4] Example histograms of zero-inflated Poisson distributions with mean of 5 or 10 and proportion of zero inflation of 0.2 or 0.5 are shown below, based on the R program ZeroInflPoiDistPlots.R from Bilder and Laughlin. [1]

  6. Stokes' law - Wikipedia

    en.wikipedia.org/wiki/Stokes'_law

    Note the minus sign in the equation, the drag force points in the opposite direction to the relative velocity: drag opposes the motion. Stokes' law makes the following assumptions for the behavior of a particle in a fluid: Laminar flow; No inertial effects (zero Reynolds number) Spherical particles; Homogeneous (uniform in composition) material

  7. Force field (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Force_field_(chemistry)

    Part of force field of ethane for the C-C stretching bond. In the context of chemistry, molecular physics, physical chemistry, and molecular modelling, a force field is a computational model that is used to describe the forces between atoms (or collections of atoms) within molecules or between molecules as well as in crystals.

  8. Boltzmann equation - Wikipedia

    en.wikipedia.org/wiki/Boltzmann_equation

    The general equation can then be written as [6] = + + (),. where the "force" term corresponds to the forces exerted on the particles by an external influence (not by the particles themselves), the "diff" term represents the diffusion of particles, and "coll" is the collision term – accounting for the forces acting between particles in collisions.

  9. Morse potential - Wikipedia

    en.wikipedia.org/wiki/Morse_potential

    The Morse potential, named after physicist Philip M. Morse, is a convenient interatomic interaction model for the potential energy of a diatomic molecule.It is a better approximation for the vibrational structure of the molecule than the quantum harmonic oscillator because it explicitly includes the effects of bond breaking, such as the existence of unbound states.