Mathematically "product" means the result of multiplying numbers. It simply doesn't make sense to talk about the "product" of a single number as in "product of v is μg" or "the product of m is weight". Perhaps you mean it the other way- weight is the product of mg. That is "mass times the acceleration due to gravity of an object is the force on that object due to gravity"- by definition its "weight". I'm not sure what you could mean by "v is the product μg", if that is what you intend, because you have not told us what μ is and it is not a standard symbol. Sometimes μ is used for the "coefficient of drag" but that doesn't make sense here. Assuming g is the acceleration due to gravity and v is velocity, their standard meanings, since v would have units of "meters per second" and g "meters per seconds squared", μ would have to have units of "seconds"- it would have to be a "time". Is that correct?