First 153 words of the document:
Newton's laws of motions
1st law: A body will remain at rest or move at constant speed unless an external force acts
on it. This means that a body moving at constant speed has no resultant force acting on it.
2nd law: Resultant force acting on a body produces an acceleration which is proportional to
the resultant force. F = ma
3rd law: For every action there is an equal but opposite reaction.
Label the forces and acceleration including their direction on a diagram.
If the lift is decelerating then either use a negative acceleration in the direction of
motion or use a positive acceleration in the opposite direction to the motion.
Choose which direction you are taking as positive
If velocity is constant then upwards force is equal to downwards force and the
reaction equals the weight