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 Three Laws of Motion and his Law of Gravity are probably the most famous of all physics. They govern the motion of objects that we see in our everyday lives. Newton's First Law of Motion says that an object will remain in its state of motion unless acted upon by force. Essentially, this means that if an object is not moving, it will remain still until a force (a push or pull) acts on it.