What is the distinction between mass and weight according to newton's second law of motion?

Answer 1

Newton's 2nd Law states: mass x acceleration = Force.

The Mass of an object is constant, but its weight is variable. Acceleration due to gravity is fairly even on the earth, so to find the quantity of matter in an object, in other words its mass, you can weigh it and get an accurate answer.

The confusion comes in because weight is commonly given in kilograms, but weight is actually a force and is properly measured in Newtons. 1 kg of matter on earth is still 1 kg of matter on the moon, but its weight in Newtons (N) varies to the gravitation. Using ma=F

On the earth: 1 kg mass x 9.8 m/s^2 = 9.8N weight

On the moon: 1 kg mass x 1.6 m/s^2 = 1.6N weight

It's one of those awkward bits of language where the common meaning of a word like kilogram is different from its scientific meaning, and it is well to be aware that scientists measure weight in Newtons not kilograms