Center of Gravity Satellite
It is the point in a body around which the A satellite is a moon, planet or machine
resultant torque due to gravity forces vanish. that orbits a planet or star. For example,
Near the surface of the earth, where the gravity Earth is a satellite because it orbits the
acts downward as a parallel force field, the sun. Likewise, the moon is a satellite
center of gravity and the center of mass are the because it orbits Earth.
same. Usually, the word "satellite" refers to a
machine that is launched into space and
Mass (m) moves around Earth or another body in
It is the quantity of matter in a body The world"s first artificial satellite, the
regardless of its volume or of any forces Sputnik 1, was launched by the Soviet
acting on it. Union in Oct. 4, 1957.
It should not be confused with weight, The path a satellite follows is an orbit. In
which is the measure of the force of the orbit, the farthest point from Earth is
gravity acting on a body. the apogee, and the nearest point is the
Its unit is the kilogram (kg). perigee.
mass = Force / acceleration [m = F/a ]
mass = momentum / velocity [ m = p/v ] Important types of Satellite
mass = weight / acceleration of gravity [
m = W/g ]
Satellites" : to destroy enemy warheads,
satellites, and other space assets.
Weight (W) Astronomical satellites : observation of
distant planets, galaxies, and other outer
It is the force exerted on a body by gravity space objects.
and calculated as the mass times the Biosatellites : to carry living organisms,
acceleration of gravity, w = mg. generally for scientific experimentation.
Its unit is the newton (N). Communications satellites :
For an object in free fall, so that gravity is telecommunications
the only force acting on it, then the Navigational satellites : use radio time
expression for weight follows from signals transmitted to enable mobile
Newton"s second law. receivers on the ground to determine their
W = mg exact location.
Weight of object = mass of object x Reconnaissance satellites : Earth
acceleration of gravity observation satellite or communications
satellite deployed for military or
Weight of a PERSON inside the Lift intelligence applications.
Earth observation satellites : non-
military uses such as environmental
monitoring, meteorology, map making etc.
Weather satellites : used to monitor
Earth"s weather and climate.
Manned spacecraft (spaceships) : large
satellites able to put humans into (and
beyond) an orbit, and return them to Earth.
Space stations : man-made orbital
structures that are designed for human
beings to live on in outer space.