electrostatics

Newton's law of universal gravitation

every particle in the universe attracts every other particle, with a gravitational force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres

coulombs law

magnitude of the electrostatic force exerted by two points charge on each other is directly proportional the product of the magnitude of the charges and inversely proportional to the square of the distance between them

electric field lines

region in space in which an electric charge experiences a force. the direction of the electric field at a point is the direction that a small positive test charge would move if placed at that point

electric field strength

electrostatic force experienced per unit positive charge

weightlessness

sensation experienced when all contact forces are removed