newton’s first law of motion

an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a net external force

common mistakes and misconceptions

mass is how much matter an object is made from; it is constant. the weight of an object is the force exerted by gravity on that object, so it depends on the local g value.

ex.: the value of g on the moon is much lower than on earth, so an object weighs less there, but the mass does not change.

newton’s second law of motion

the acceleration and net external force are directly proportional, and there is an inversely proportional relationship between acceleration and mass