Equations of motion system). Particle does not exert a torque on itself. Some examples of Newton's law include describing the motion of a simple pendulum, and a damped, sinusoidally driven harmonic oscillator, For describing the motion of masses due to gravity, Newton's law of gravity can be combined with Newton's second law. For two examples, a ball of mass thrown in the air, in air currents (such as wind) described by a vector field of resistive forces , where is the gravitational constant, the mass of the Earth, and is the acceleration of the projectile due to the air currents at position and
Newton's laws of motion way one can consider the laws to be a definition of these quantities. Newtonian mechanics has been superseded by special relativity, but it is still useful as an approximation when the speeds involved are much slower than the speed of light. The first law states that if the net force (the vector sum of all forces acting on an object) is zero, then the velocity of the object is constant. Velocity is a vector quantity which expresses both the object's speed and the direction of its motion; therefore, the statement that the object's velocity is constant is a statement that