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Motion
Term | Definition |
---|---|
motion | a change in an object's position relative to a reference point |
displacement | the distance and direction of an objects change in position (start and stop) |
speed | the distance an object travels per unit of time |
velocity | includes speed of an object and the direction of its motion |
momentum | an object's mass and velocity |
acceleration | the rate of change of velocity |
force | a push or pull on an object |
net force | the sum of all of the forces acting on an object |
unbalanced force | the net force is not zero on an object |
balanced force | the net force is zero on an object |
friction | the force that opposes motion of objects in contact. |
kinetic friction | the force between two moving objects in contact |
static friction | the force between two objects in contact that are stationary |
inertia | the tendency of an object to resist a change in motion |
gravity | an attractive force between all objects that have mass |
weight | the gravitational force exerted on an object |
Newton's First Law of Motion | an object moves at a constant velocity unless an unbalanced force acts on it. |
Newton's second law of motion | an objects acceleration is in the same direction as the net force on the object and is equal to the net force divided by its mass. |
Newton's third law of motion | when one object exerts a force on a second object, the second object exerts a force on the first one that is equal in strength and opposite in direction |
Air resistance | a force that opposes motion of objects that move through the air |
terminal velocity | the maximum speed an object will reach when falling through a substance such as air. |
free fall | when gravity is the only force acting on an object |
Law of conservation of momentum | if no external forces act on a group of objects, their total momentum does not change. |