Weight, Mass and Gravity

Mass

Mass is a measure of how much matter (stuff) an object is made up of. It is measured in Kilograms (kg).

Weight

Weight is the force directed to the centre of the Earth, experienced by objects of mass, due to the attraction of gravity. As with all other forces this is measured in __________ (__________). It is proportional to the mass of the object and the strength of gravity between them. Close to the Earth the strength of gravity is approx 10N per Kg.

Weight = mass × gravitational field strength

W = m g
where:
W = Weight in __________, __________
m = mass in __________, __________
g = Gravitational Field Strength in __________, __________

Example

An object with a mass of 10__________ has a weight of __________ __________.

Gravity

The area around an object in which its gravitational effects are felt, is known as its gravitational field. Gravitation field strength __________ as the distance between objects increases.

It is gravity that keeps planets, stars, solar systems and even galaxies together. The orbits of planets, while nearly circular, are in fact __________. Comets have a far more exaggerated elliptical orbit, which takes them close to the __________ and then very far away again

When objects are in orbit they are continually __________ around a larger one. Two objects together will fall at the same rate and therefore appear to __________ next to each other.