The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The presence of an unbalanced force will accelerate an object - changing its speed, its direction, or both its speed and direction. According to Newton, an object will only accelerate if there is a net or unbalanced force acting upon it. Objects at equilibrium (the condition in which all forces balance) will not accelerate. The first law - sometimes referred to as the law of inertia - states that if the forces acting upon an object are balanced, then the acceleration of that object will be 0 m/s/s.
Newton's first law of motion predicts the behavior of objects for which all existing forces are balanced.
