Free Tidal Force Calculator

Compute the differential tidal acceleration across an object of size dr due to a mass M at distance d: a_tidal = 2 G M dr / d^3.

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Tidal Acceleration

0.0000021985 m/s2

Tidal Acceleration vs Tidal Source Mass

View formula & how it works →

Tidal Force

Tidal forces arise because gravity varies with distance. The near side of an object feels a stronger pull than the far side.

Formula

a_tidal = 2 G M dr / d cubed

  • *M* = mass of the tidal source
  • *d* = distance from the source
  • *dr* = size of the object being tidally stretched

    • This is the leading term in a Taylor expansion of the gravitational field.

    Example Calculation

    Moon's tidal pull across Earth (M = 7.342e22 kg, d = 3.844e8 m, dr = 1.274e7 m).

    1. 01a = 2 G M dr / d cubed
    2. 02G M = 6.674e-11 * 7.342e22 = 4.899e12
    3. 03d cubed = (3.844e8)^3 = 5.68e25
    4. 04a = 2 * 4.899e12 * 1.274e7 / 5.68e25
    5. 05a = 2.20e-6 m/s2

    Frequently Asked Questions

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