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Motion and Forces
Term | Definition |
---|---|
reference point | an object that appears to stay in place |
motion | when an object changes position over time when compared to a reference point |
speed | the rate at which an object moves |
velocity | the speed of an object in a particular direction |
acceleration | the rate at which velocity changes |
deceleration | acceleration in which velocity decreases |
centripetal acceleration | acceleration that occurs in a circular motion |
force | a push or a pull on an object |
newton | (N) The SI Unit of force |
net force | the force that results from combining all the forces exerted on an object |
unbalanced force | forces on an object that cause the net force to be a number other than zero |
balanced force | forces on an object that cause the net force to be zero |
contact force | forces exerted on objects when objects touch |
non-contact force | forces that are exerted on objects without touching the objects |
friction | a force that opposes motion between two surfaces that are touching |
sliding friction | a force that opposes motion when two surfaces slide past each other |
rolling friction | a force that opposes motion when an object is on rollers or wheels |
fluid friction | a force that opposes motion in a fluid, such as liquids or gases |
static friction | a force that opposes motion when a force is applied to an object and the object does not move |
lubricant | a substance applied to surfaces to reduce the friction between them |
gravity | a force of attraction between objects that is due to their masses |
weight | a measure of the gravitational force exerted on an object |
mass | the amount of matter that something is made of |
law of universal gravitation | law that states that all objects in the universe attract each other through gravitational force ; depends on their masses and the distance between them |