Forces are quantitative descrpitions of interactions of bodies that either push each other away or pull closer toghether. The magnitude of pulling or pushing is expresseed in terms of a quantity know as Newtons abbreviated as N.
According to Isaac Newton, there are three fundamental laws regarding forces:
1. At equilibrium the sum of all forces equal to zero: ΣF = 0
2. An external force acting on a body will accelerate the body at the same direction(vector) of the force. Thus, the sum of all forces is the product of the mass and the acceleration: ΣF = ma.
3. If a body a excerts a force on body b, then body b will excert the same amount of force on body a: Fa = Fb.