Physical+Science

**Force and Motion**

 * balance/equilibrium = forces are equal; forces always occur in pairs**
 * friction = a force that resists motion; caused by two surfaces sliding past one another;****friction**
 * always generates HEAT **


 * gravity = force that pulls all objects towards the center of the Earh**
 * magnetism = a force caused by attraction or repelling in a magnetic field**
 * 6 simple machines: lever, inclined plane, pulley,screw, wheel and axle, wedge**