Gravity ALWAYS does that, and electrostatic force does it when two objects have opposite charges.
Only if a force acts upon it, it can move.
A spontaneous reaction is a term that is best describe to a type of reaction wherein it is started without even with the help of an outside force. In addition to that, this kind of reaction is commonly driven by the forces of enthalpy and entropy which are essential concepts to thermodynamics.
Answer:
because all objects fall at a rate of 9.8m/s²