Lauren_Brianna

4A Test Review "toc " =Circular Motion= -the movement of an object at constant speed around a circle with a fixed radius. -axis: straight line around which rotation takes place -rotation: object turns around an internal axis. (ex): Ice Skater -revolution: object turns around an external axis. (ex): Earth around the sun

Rotational Speed
-Linear Speed: distance/time -Tangential Speed: speed along a circular path. -Rotational Speed: number of rotations per unit of time

Centripetal Force/Centripetal Acceleration
centripetal force is a force that causes an object to follow a circular path. centripetal acceleration always points towards the center of the circular motion.

=Universal Gravitation and Mass= - As the mass of either object or both objeect increases, the force of gravitational attraction increases. - Newton's law of universal gravitations applies to all objects. - As the distance of the 2 objects increases, the force of attractions is expotentially smaller.

Universal Gravitation Formula:
__Fgrav=m1 m2__ d2 =Friction=

Static Friction Force
- Exerted on one surface by the other when there is no relative motion between the two surfaces.

Kinetic Friction Force
- Force exerted on one surface by the other when the surfaces are relative motion. =Gravity and Weight= -Gravity: a constant force exerted by objects that have mass. -Weight: the pull of gravity. =Weight and Gravity on the Earth and Moon= -An object on Earth's surface weighs more than the same object high above the Earth's surface. -As the object gets farther from the center of the earth, the force pulling on the object is less. -The earth's mass is approximately six times that of the moon.

=Coulomb's Law and Electric Field= -Coulomb's Law: the relationship among electrical forces, charges, and distance. -Coulomb's Law was discovered by a French scientists, Charles Coulomb in th 18th century. -Q= charge (C for Coulomb) D= distance -SI unit for electrical charge is Coulomb (C) = = =Electric Field= - A vector quanity that relates the force exerted on a chance to the size of the charge.

Electric Field Lines
- Direction of the line indicate the charge of the field. - Away from + charged objects - Toward a - object - Strength of the field is denoted by the spacing between the lines (close = strong)

Electric Potential Difference
- Causes charges to move - W = Work (J) - V = Potential Difference - Q = test charges (C)

Grounding
- Touching a body to Earth to eliminate excess charge.



Electric Current
- Flow of charged particles current always flows from a higher potential difference to a lower p.d - Flow will stop when 0. - For current to continue to flow, electrical sourse is needed.

Electrical Energy Sources
- Voltaic or galvanic cells converts chemical to electrical energy.

Photovoltaic
- Changes solar into electrical energy.

Generators
- Convert kinetic energy into electrical energy.