Final answer:
The formula not associated with Newton's 2nd Law is D. m = a/F. Newton's second law is usually represented as F = ma. Options A, B, and C are all correct derivations or rearrangements of Newton's second law, while option D is incorrect.
Step-by-step explanation:
The formula NOT associated with Newton's 2nd Law is D. m = a/F. Newton's second law states that the net external force (Fnet) on an object is equal to the mass (m) of the object multiplied by its acceleration (a), which can be mathematically expressed as F = ma or Fnet = ma.
The other formulas, A. F = ma, B. m = F/a, and C. a = F/m, are derivations or rearrangements of this law, emphasizing different aspects such as solving for mass or acceleration. However, option D. m = a/F does not correctly represent any manipulation of Newton's second law and is incorrectly formulated.