Newton’s first law of motion tells us that an object will move unless acted on by an unbalanced force.

Newton’s first law of motion tells us that an object will move uniformly unless acted on by an unbalanced force.

Explanation:

Newton's first law of motion states that if no resulting force acts on an object, no speed change of that object can occur. The speed will therefore remain unchanged: both size and direction of the speed remain constant.  

This law comes directly from Galileo and has been taken over by Newton. The first law is also called the law of inertia: an object on which no external forces act is at rest or carries out a unanimous, linear movement.  

Therefore, an object is not accelerated without force. Without the occurrence of a force, an object maintains a constant speed, which can be 0 (case of rest).