p.28-35+in+notebook

Circular Motion Notes
Circular Motion- the movement of an object at conatant speed around a circle with fixed radius Axis- straight line around which rotation takes place Rotation- object turns around an internal axis Revolution- object turns around an external axis Liner speed- Distance\time Tangential speed- speed along a circular path Rotational speed- number of rotations per unit of time

Tangential speed is radial distance times therotational speed V=rw

Force that causes an object to follow a circular path Fnet=mv^2/r

Centripetal acceleration- Always point toward the center of the circular motion Period(T)= time needed for an object to make one complete revolation Distance traveled- circumference

Circumference= 2pieR=pieR

Centrip/acceler= the velocity squared divided by the radius

Ac=v^2/r

Revolutions= distance trveled by circumference Revolutions= distance/circumference

Newton's law of universal Gravitation
Newton & Gravity- newton beleved that gravitation forces were responsible for the acceleration of objects on the moon and on earth Suppose we fire a cannon horizontaly from a high mountain; the projectile will eventually fall to earth Newton resoned that if the right cannon projected the cannon ball with the right velocity it would travile around the earth falling in the field but never reaching the earth Newton concluded that any two objects in the universe exert gravitational attraction on each other Newtons law of universal gravitation applies to all objects.

Universal gravitation and mass

as the mass of either object or both object increases, the force of gravitational attraction increases Effect of mass on gravity 1M 1F 1M 1M 2F 2M 2M 4F 2M As the distance seperating two objects increases the force of attraction is exponetially smaller Fgrav=G m1 m2/d^2 G= universal gravitation constant G=6.67x10^-11 Nm^2/Kg^2

Friction
Newton's law tells you it should move unless there is a second horizontal force on the object in the opposite to your force and equal in size. That force is called the static friction force. the kinetic friction force is the force exerted on one surface by the other when the surfaces are in relative motion.

Kinetic friction force

Ff1 kinetic= MkFn

In this equation Mk is a proportionality constant called the kinetic co efficient of friction The static friction force is related to the normal force by this expression.

Static friction force O =or< Ff, Static <or=MsFn

Coulomb's Law/ Electric Fields Notes
Relation ship among electrical forces, charges, & distance Like newtons law of gravity, but can be attrative or repulsive discoverd by french charls coulomb in the 18th centery

F= K qa qb/ d^2 F= force K=(electrical proportionality constant) q= charge c (C for comlomb) d=distance(m)

the si unit of mesure for electrical charge is a coulomb(c) Charge of 1 proton is+ 1.6x10^-19c/charge 1 electron is -1.6x10^-19c Charge(q) of a particale is not a vectorquantity DO NOT PUT THE NEGATIVES IN THE FORMULA two charges seperated by 0.030m. Object A has a charge of +6.0c write object B has a charge of +3.0c. What is the force of object A? G:K=9.0x10^-9Nm^2/C^2 D=0.03m qA:6.0C qB:3.0C U:F=?N E:F=k qA qB/d^2 S:F=9.0x10^-9Nm^2/C^2x 6.0Cx3.0C/(.03m)^2 S:F=1.8x10^14N

E- Field- Vector quantity that relates the force exerted on a charge to the size of the charge The magnitude of the field is measured in N/C(newtons/coulombs) Direction of aerrows indicates charge of the field. Away from is a positive charce To is a negitive Causes charges to move ^v= W on q/q Grounding- touching a body to earth to eliminate excess charge. Earth allows almostany electric flow untill Electric potential difference is at zero