Summary Newtons Law of Universal Gravitation

NEWTONS LAW OF UNIVERSAL
GRAVITATION

NEWTONS LAW OF UNIVERSAL GRAVITATION
Newton’s law of universal gravitation – every object in the universe attracts
every other object in the universe with a force that is directly proportional to
the product of their masses and inversely proportional to the square of the
distance between their centres
 The gravitational force of attraction between any two masses
 The force depends on the masses of the earth and you, the force
weakens with distance
(m 1 x m2)
F=G always a force of attraction
r2

 F = gravitational force of attraction
 G = 6.7 x 10-11
 m1 and m2 = masses of the objects
 r = distance between their centres
The inverse square law = distance doubles, force quarters. Distance triples
force ninths



GRAVITATIONAL FIELD STRENGTH
Gravitational field strength – the gravitational force exerted on an object per
kg of the objects mass
g = 9.8m.s-2
This is a measure of the Earths gravitational field strength. The earths
gravitational field strength is 9.8N.kg-1 this means every kg of mass will
experience 9.8N of attractive force