Equilibrium -The sum of all the forces acting on the object is zero, which is the first condition of it and it has two forms. Law of Inertia -The body will remain at rest or move at constant velocity unless acted. upon by an external net force or unbalanced force.
Newton's first law states that when the vector sum of all forces acting on an object (the net force) is zero, the object is in equilibrium. If the object is initially at rest, it remains at rest. If it is initially in motion, it continues to move with constant velocity.