Physics+Wurkk

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__**Centripetal Force**__
Ex: Force holding occupants safely in a rotating carnival ride -Distance traveled = Circumfrence -Circumfrence = 2 p r = p d
 * A force that causes an abject to follow circular path
 * Centripetal Force always points toward the center of the circular motion
 * Period (T) = Time needed for an object to make on complete revolution

**__Rotational Speed__**
Linear Speed- Distance/time Tangential Speed- Speed along a circular path Rotational Speed- Number of rotations per unit of time Ex: Carousel horses travel at the same rotational speed but different tangential speed

__**Friction**__
Static Friction Force-the force that opposes the start of relative motion between the two surfaces in contact
 * Friction is everywhere; you need it to start and stop a bike and a car

**__Kinetic Friction Force__**
F f, kinetic = µkF N (µk is a proportionality contant called the kinetic coefficient of friction)

Electric field- a vector quantity that relates the force exerted on charge to the size of the charge

 * The magnitude of the electric field is measured in N/C (Newtons/Coulomb)
 * An electric field surrounds electrically charged particles and time-varying magnet fields

* The direction of the arrows indicate the charge of the field

 * The strength of the field is denoted by the spacing between the lines (close = strong)

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