1. The Earth's Gravitational Field

Differences in Gravitational Attraction

- The density of the Earth varies - the shape of the earth - the effects of centrifugalforces which is opposite to that of the gravitational field - alitude, as the high away from warth, the lower the gravitational Attraction.

Mass

the amount of matter in an object or body. (Kg)

Weight

the force acting upon a body of mass within a gravitational field. (Newtons N)

Newton's law of gravitation

1. Every object in the Universe attracts every other object with a gravitational force 2 . This force is directly propertional to the masses of the objects 3. This force is Inversely proportional to the square of the distance between them

F = mg

F = weight or the weight force (usually used interchangeably), measured in N m = mass of the object, measured in kg g = gravitational acceleration on the object due the presence of the gravitational eld, measured in m s-2

Derivation for Gravitational Attraction on other planets

F(weight) = F(Gravity) m(object) * g(planet) = g*m(object)*m(planet) / d^2 g(planet) = Gm(planet)/d^2

Gravitational Field

The force field that exists around every mass or group of masses

F = Gm1m2/d^2

m1 and m2 = masses of the two objects, measured in kg d = the distance between the two objects measured from the centre of each object G = the universal gravitational constant, that is, 6.67 × 10-11 N m2 kg-2