What is meant by saying that 'force is due to an ineteraction'? Give an example to illustrate your answer.
Interaction involves two objects. In interaction, each object acts in such a way, as to have an effect on the other object. Interaction of one object with another object results in force between two objects. At least two objects must interact with each other for a force to come into play. If there is no interaction between two objects, no force can show its effects.
Suppose a man is standing behind a stationary car, there is no interaction between man and the car, so no force act on the car and hence the car does not move. If the man pushes the car with his hands due to which the car starts moving, there is an interaction between man and a car. During this interaction force arises which acts on the car and makes it move in the direction of applied force. If both the objects are capable to applying force on each other, then the interaction between them can be pulling or pushing.