Why because it isn't part of the fundamental units which is MLT which stands for mass,length and time.....MLT are the units that brings out the derived units that's why it is called derived units because it is derived from fundamental units so Newton/force is not part of the fundamental unit and if we find the dimension of force you will see that it will be L^2T^-2.....which means it is derived from fundamental unit which makes it a derived unit....Thank you for the question
Answer: Newton, the unit of force, is defined based on Newton's Second Law (F=ma), as the force required to give a mass of one kilogram an acceleration of 1 meter/second2. Thus, it is derived from these other units.
