| A | B |
|---|
| force | a push or pull that acts on an object |
| newton | the SI unit for force, equal to the force that causes a 1- kilogram mass to accelerate at a rate of 1 meter per second squared |
| net force | the overall force acting on an object after all the forces are combined |
| friction | a force that opposes the motion of objects that touch as the move past each other |
| static friction | a friction force that acts on objects that are not moving |
| sliding friction | a friction force that opposes the motion of an object as it slides over a surface |
| rolling friction | a friction force that acts on rolling objects, caused by the change in shape at the point of rolling contact |
| fluid friction | a friction force that opposes the motion of an object through a fluid |
| air resistance | fluid friction acting on an object moving through air |
| gravity | the attraction between any two objects because of their masses |
| terminal velocity | the constant velocity of a falling object when the force of air resistance equals the force of gravity |
| projectile motion | the curved path of an object in free fall after it is given an initial forward velocity |
| inertia | the tendency of an object to resist a change in its motion |
| mass | a measure of the inertia of an object, which depends on the amount of matter the object contains |
| weight | the force of gravity acting on an object |
| momentum | the product of an object's mass and its velocity |
| law of conservation of momentum | law stating that the total momentum of a system does not chage if no net force acts on the system |
| electromagnetic force | a force associated with charged particles, which has two aspects, electric force and magnetic force |
| strong nuclear force | the powerful attractive force that binds protons and neutrons together in the nucleaus |
| weak nuclear force | a powerful attractive force that acts over a short range |
| gravitational force | an attractive force acts between any two objects |
| centripetal force | a force that continuously changes the direction of an object to make it move in a circle |
