Free · Physics models
Newtonian Force Between Two Point Masses
Calculate attractive-force magnitude or inverse masses and separation using Newtonian gravity.
- Formula & worked example
- Private in your browser
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Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
force = 1.0011e-10. This worked example uses the displayed units and declared assumptions.
force=gravitational_constant*mass_1*mass_2/distance^2; force_mantissa = one_way(force <= 0 ? 0 : ((force >= 1e-6 and force < 1e3) ? round(force/10^(floor(log10(force))),2)*10^(floor(log10(force))) : round(force/10^(floor(log10(force))),3))); force_exponent = one_way(force <= 0 ? 0 : ((force >= 1e-6 and force < 1e3) ? 0 : floor(log10(force))))
Worked example
Enter these known values and leave the other values blank.
- Mass 1 (M)
- 2 kg
- Mass 2 (m)
- 3 kg
- Distance (R)
- 2 m
- Gravitational force (F)
- 1.0011e-10 N
Assumptions and limitations
- Point masses or spherical masses outside their radii are assumed. G=6.67430e−11 SI is a measured reference value, not an exact constant. Force is a positive magnitude; relativistic and nonspherical effects are omitted. Scientific-notation notes deliberately round display intermediates only.
- Clear an unknown to solve a supported inverse; keep known values fixed with locks. Singular or underdetermined inverses may remain incomplete.
Common questions
What assumptions apply?
Point masses or spherical masses outside their radii are assumed. G=6.67430e−11 SI is a measured reference value, not an exact constant. Force is a positive magnitude; relativistic and nonspherical effects are omitted. Scientific-notation notes deliberately round display intermediates only.
Which unknowns can I solve?
Editable controls preserve the supported captured inverse branches. Clear the desired unknown and provide enough independent known quantities; singular or underdetermined inverses may remain incomplete.
References
Translate scientific-notation display helpers to pinned local arithmetic. Physical force and its five inverses retain G=6.67430e−11 SI. Mantissa uses three significant figures for 1e−6≤F<1e3 and four outside that display interval; exponent is zero inside and floor(log10(F)) outside. Invalid nonpositive forces use zero display intermediates while physical guards reject them.