1.1.1 When 2 objects interact, the
force on one object (the action
force) is matched by an equal
and opposite force (reaction
force) on the other
184.108.40.206 e.g. when a rocket move through space, the rocket
engines push out hot gas backwards at high speed.
The reaction force makes the rocket move forwards.
The action is expelling the hot gas. The action is the
forward force on the rocket
1.2 Resultant forces
1.2.1 A single force that replaces a number of
forces with the same effect
1.2.2 If two forces act in the same direction they add together
220.127.116.11 If they act in opposite directions they subtract