The Free Body Diagram Newton's 2nd Law says that for an object F= ma Key phrase here is for an object. So before we can apply F= ma to any given object we isolate the forces acting on this object We obtain the fbd Physics 121: Lecture 3, Pg 8Physics 121: Lecture 3, Pg 8 The Free Body Diagram Newton’s 2nd Law says that for an object F = ma. Key phrase here is for an object. So before we can apply F = ma to any given object we isolate the forces acting on this object: We obtain the FBD