What was Isaac newtons 2 rule?

Answer 1

The second law is about how the force affects the motion. A relatively small force could make, say, a tennis ball accelerate a lot (e.g. changing its direction completely), but could not make the motion of, for example, a truck change very much. This is because the mass of the objects are very different. Similarly, if two objects had the same mass, a large force would change the motion a lot, where as a small force not so much. So the change in motion depends on the size of the force and the mass of the object.

Answer 2

Isaac newton's second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Mathematically, this can be expressed as F = ma, where F is the net force, m is the mass of the object, and a is the acceleration.