Chapter 16: Electric Force and Coulomb's Law

Lecture #2

forces

push, pull, tension in a rope, friction, springs, gravity

newton’s laws describe

how forces lead to changes in motion

the SI unit of force is

Newton (kg m/s²)

force is a vector

there is direction and magnitude

the law of superposition states

that the net force is equal to the vector sum of all the individual force

gravity is an inverse square law meaning that

the strength of the force is inversely proportional to the square of the separation

newton’s third law

the magnitude of forces are equal to one another but have opposite directions

coulomb’s law describes the

electrostatic force between two charges (stationary charges and small, well separated charged objects)

electric force has

a direction and magnitude

coulomb’s first law describes the

direction of electric force

coulomb’s second law describes

the magnitude of the electric force

the electric force can be

attractive or repulsive

if they have the same sign charges, the

force is repulsive

if they have opposite sign charges, the

force is attractive

the force points along the line

joining the two charges

the sign of the charge (positive or negative) determines

the direction of the force

the magnitude of the force is proportional to

the product of the magnitude of the two charges

the magnitude of the charges determine the

magnitude of the force

the magnitude of the force is inversely proportional to the

swore of the separation between the two charges

coulomb’s constant (k)

8.988 × 10^9

superposition tells us

we have to add these two individual forces together to get the net force

if two vectors are in the same direction

add them together

for two perpendicular vectors acting on an object

use parallelogram method to find the net vector