Section A: What is Force
 
Law of Force, Origin of Force
 
What is Force
 
The Intuitive Meaning of Force
 
You feel a force when someone pushes you.
 
A force is a push or pull upon an object by another object when the two objects interact with each other.
 
The Effect of a Force
 
A force is a push or pull. So we consider the effect of such push and pull to narrow down the actual meaning of ‘Force’.
 
Let us consider the motion of an object exerted by a force, for example, dragging a luggage. Let us use our intuition to judge: which of the following intuition is correct.
 
Intuition 1:
 
A pulling force is needed to keep the motion of the luggage.
 
That is, a force is needed to keep an object in motion.
 
Intuition 2:
 
A pulling force is needed to start the motion of the luggage.
 
That is, a force is needed to speed up the motion of an object.