Using dimensional analyisis to verify formulae

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Using dimensional analysis, the discussion focuses on verifying the correctness of two gravitational force formulas: FG = G m M / r^2 and FG = G m M ./ r. The gravitational constant G has units of m^3s^-2kg^-1, which must be consistent with the units of force (kg·m/s^2). Analyzing the units for both formulas reveals that only formula (a) yields consistent units for force, while formula (b) does not match. Thus, formula (a) is validated as the correct representation of the gravitational force between two masses. Dimensional analysis proves essential in confirming the validity of physical equations.
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Heres a question I never figured out.

"Using dimensional analysis, determine which formula (a) or (b) is correct for the description of the force due to gravity between a body of mass m (kg) and another of mass M (kg) separated by a distance of r (m). The gravitational constant G has units (m^3s^-2kg^-1)
(a) FG = G m M / r^2 (b) FG = G m M ./ r"

I've been looking up dimensional analysis but can't find any information relating to validating formulae.
 
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For an equation to be physically meaningful, the units on each side must match. Check the units in these two and see what you find.
 

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