What is the cause of an acceleration or a change in a objects motion ?

speed , force, inertia, or velocity

 

Force

Objects remain in a state of rest or a state of motion unless acted on by an unbalanced force and Newton's Second Law of motion states that the acceleration of an object is proportional to the force applied and inversely proportional to the mass of the object.

Step-by-step explanation

Forces affect how objects move and they may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity.

Acceleration is a change in velocity.