What is the SI unit of force:

Concept: We know that force is a physical quantity that changes or may tend to change the state of rest or the state of motion of an object.
According to Newton's second law of motion, force is defined as the product of mass and acceleration. i.e $F=m\times a$

Here m is mass and its SI unit is kg. And a is acceleration and its SI unit is $m/s^2$ because acceleration is defined as the rate of change of velocity with respect to time is called acceleration.
Then $F=kgm/s^2=1N$
Hence, the SI unit of force is N.