Gravitational and Electric fields definitions Flashcards
Coulomb’s law of force
for two point charges Q1 and Q2 at distance apart r, the force F between the two charges is proportional to the product of the charges and inversely proptional to the distance between them squared
Electric field strength E
at a point in an electric field, is the force per unit charge on a small positively charged object at that point in the field.
Electric potential V
at a point in an electric field is the work done per unit charge on a small positively charged object to move it from infinity to that point in the field.
Equipotential
a line or surface in a field along which the electric or gravitational potential is constant.
Escape velocity
the minimum velocity an object must be given to escape from the planet when projected vertically from the surface.
Geostationary satellite
a satellite that stays above the same point on the Earth’s equator as it orbits the Earth because its orbit is in the same plane as the equator, its period is exactly 24 hours and it orbits in the same direction as the Earth’s direction of rotation.
Gravitational field
the region surrounding an object in which it exerts a gravitational force on any other object.
Gravitational field strength g
the gravitational force per unit mass on a small mass placed at a point in the field.
Gravitational force
an attractive force that acts equally on any two objects due to their mass.
Gravitational potential V
at a point in a gravitational field is the work done per unit mass to move a small object from infinity to that point
Gravitational potential energy
the work done to move a small object from infinity to that point.
Inverse-square laws (force)
when the force is inversely proptional to the square of the distance between the two objects.
Kepler’s third law
for any planet, the cube of its mean radius of orbit r is directly proportional to the square of its time period T (T2 is proportional to r3)
Newton’s law of gravitation
the gravitational force between two masses is proptional to the product of the masses and inversely proportional to the distance between them squared.
Permittivity of free space
the charge per unit area in coulombs per square metre on oppositely charged parallel plates in a vacuum when the electric field strength between the plates is 1 volt per metre.
