Electrostatic Forces

There are two kinds of electric charge.

like charges repel ; unlike charges attract

Electric charge is quantized.

That is, when an object is charged, its charge is always a multiple of a fundamental unit of charge.

Charge measurement

C ; Coulumb

F

Electrostatic force

Q or q1

First particle

q or q2

Second particle

K - constant

9×10^9

electrical conductor

material in which charges can move freely.

electrical insulator

material in which charges cannot move freely.

Insulators and conductors

can be charged by contact

induction

process of charging a conductor by bringing it near another charged object and grounding the conductor.

A surface charge can be induced on insulators by polarization.

With polarization, the charges within individual molecules are realigned such that the molecule has a slight charge separation.

Inverse Squared Law

For every distance (r) from the source (S), intensity decreases by r2

Universal Law of Gravitation:

any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

1C

charge of 6.25 x 10^18 protons

Conductors in Electrostatic Equilibrium

The electric field is zero everywhere

inside the conductor.

 Any excess charge on an isolated conductor

resides entirely on the conductor’s outer

surface.

 The electric field just outside a charged

conductor is perpendicular to the conductor’s

surface.

 On an irregularly shaped conductor, charge tends

to accumulate where the radius of curvature of

the surface is smallest, that is, at sharp points.

When solving for triangle electrostatic force problems

Step 1: Find A-b, A-C, B-C ising coulumb’s law and state whether it’s repulsive or attractive

Step 2: find the net force by using the direction each force is going in so it would be √(force 1)²+(force 2)²

Step 3: Find the angle by using tan-1 |y force/x force| = wtv degree and state whether it is below or above (-)x

capacitor

is a device that is used to

store electrical potential energy.

Capacitance

is the ability of a conductor to store energy in the form of electrically separated charges

Farad (F)

SI unit for capacitance which equal a coloumb per volt