Newton's+Laws+of+Motion

[| Newton's Laws of Motion] : http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion

An object will continue in a state of rest or uniform motion unless acted upon by an external force
 * Newton's First Law**

As an example, a ball sitting on the ground will remain stationary unless an external force acts on it (i.e. it is kicked). Or a space ship will continue to move (since there are no resistant forces in space) unless it is acted upon, so the rockets fire and it will either change direction or accelerate in the direction it is travelling.

The rate of change of momentum of an object is directly proportional to the force acting on the object. And from this law we can get the equation...
 * Newton's Second Law**

force = mass x acceleration f = ma

If the object is falling, the acceleration will be g so 9.81

When two objects interact, the forces they exert on each other are equal and opposite Two gas particles are travelling towards each other with a force of 10N. When they collide, they will exert a 10N force on each other in the opposite direction, so they will then bounce away at exactly the same force.
 * Newton's Third Law**