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 Theory of Gravity states that every object in the universe pulls on every other object. Every object feels this force, so it is a universal force. The force is always attractive; it is always a pull, never a push. Picture the force of gravity as the tension in an imaginary rope between two objects. What factors determine the strength of the pull between two objects? The masses of the two objects are important factors. Remember that mass is a measure of the amount of material in an object. Thus, mass is a measure of the number of pullers in that object. It makes sense that the more pullers there are, the stronger the pull.