Friction- is a force that opposes the motion of objects that touch as they move past each other.
Gravity- is a force that acts between any two masses.
Acceleration- is the increase in the rate or speed of something.
Free Fall- is any object that is being acted upon only by the force of gravity.
Net Force- is the overall force acting on an object after all the forces are combined.
Balanced Force- are forces that combine to produce a net force of zero.
Unbalanced Force- is a force that results when the net force acting on an object is not equal to zero.
Momentum- product of an object's mass and velocity.
Velocity- is the speed and direction of an objects motion.
Kinetic Energy- energy that a body possesses by virtue of being in motion.
Potential Energy- the energy of a body or a system or a system with respect to the position of the body or the arrangement of the particles of the system.
Newton's 1st Law- the state of motion of an object does not change as long as the net force acting on it is zero.
Newton's 2nd Law- the acceleration of an object is equal to the net force acting on it divided by the object's mass.
Newton's 3rd Law- whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.