【Movable】 , 【mobile】 ,  【motive】  mean capable of moving or of being moved.

【Movable】 applies not to what has independent power of motion but to what can be moved by men or machines (as by lifting, drawing, pushing, or driving) or to what is not fixed in position or date.

【Mobile】 stresses facility or ease in moving or, less often, in being moved. It often describes the quality of flowing which distinguishes a fluid from a solid or which characterizes an electric current or charge or the character which distinguishes something or someone that moves or is equipped or able to move quickly and readily, or to go (as from place to place or from one condition to another), from what is slow-moving or unlikely to engage in major moves.

But equally often  【mobile】 describes features, faces, expressions of face, or thoughts which respond quickly and obviously to changing emotions, mental states, or external stimuli, often at the same time connoting either fickleness or instability or flexibility and versatility.

【Motive】 implies a moving only in the transitive sense of driving, or causing movement, or impelling to action; the term is used chiefly with reference to power or energy or their sources (as fuel, steam, or electricity) viewed as agent in a process of moving.

Even when the reference is to something which constitutes a 【motive】 for action, " 【motive】  power," " 【motive】  force," or " 【motive】 energy" is likely to be used.