Consult your doctor if: 1  Your headache symptoms occur more than 15 days a month or require frequent over-the-counter pain medicine. 2  You have a severe headache, and over-the-counter pain medicine doesn't help. 3  You miss school or work because of frequent headaches or the headaches interfere with your daily life. 4  Definition. Causes.
Newton's law of gravitation. (nt'nz) The principle that expresses the force of gravitational attraction between two bodies as a function of their mass and their distance.
Newton's Second law of motion states that the net force on an object is directly proportional to its rate of change of momentum.his is a derivation of F=MA, or net force equals mass times acceleration.. Mass is inversely proportional to the acceleration. This means that the greater the mass, the more force you will have to apply to get a greater acceleration.