Question

What is the difference between attractive and repulsive force?

Answer 1

The difference between the two forces can be understood from the way they are defined. The attractive and repulsive forces are defined for any two bodies that are under the influence of each other. Hence based on the line of action of force on one due to another we will be able to define whether the force is attractive or repulsive and accordingly differentiate between attractive and repulsive forces.

Formula used:
$N={{N}_{\circ }}{{e}^{-\lambda t}}$

Complete step-by-step solution:
Let us consider two A and B bodies separated by some distance ‘r’ in space along one dimension. Further let us assume the force on A due to B is ${{F}_{AB}}$ and that the force on B due to A be ${{F}_{BA}}$. Further let us say the force between the two is mutual. Let the vector $\overrightarrow{{{r}_{BA}}}$ be direction from A to B

If the ${{F}_{BA}}=-\overrightarrow{{{r}_{BA}}}$ and simultaneously ${{F}_{AB}}=\overrightarrow{{{r}_{BA}}}$ , then we can imply that the force on both the bodies are directed towards each other. Hence both the bodies will be moving towards each other i.e. they attract each other.
Similarly, if ${{F}_{BA}}=\overrightarrow{{{r}_{BA}}}$ and simultaneously ${{F}_{AB}}=-\overrightarrow{{{r}_{BA}}}$ , then we can imply that the force on both the bodies are directed away from each other. Hence both the bodies will be moving away from each other i.e. they repel each other.
Hence we can conclude that two bodies under the action of mutual force between the two, the attractive force brings the bodies towards each other while the repulsive force moves them away from each other.

Note: It is to be noted that the gravitational force is always attractive in nature. Whereas the electrostatic force is either attractive or repulsive. There exists a force of attraction for like charges and force of repulsion for unlike charges.