Which of the following is the cause of an acceleration or a change in an object's motion?

Net force causes an acceleration or change in the motion of an object.

Newton's first law of motion states that an object in a state of rest or uniform motion in a straight line, will continue in that state unless acted upon by an external force.

The second law states that the force applied to an object is directly proportional to the product of mass and acceleration of the object. The object tends to move in the direction of the net force.

Acceleration is defined the change in the velocity per change in the time of motion of the object.

where;

Δv is the change in velocity.

Thus, we can conclude that net force causes an acceleration or change in the motion of an object.

Learn more here:link

Net force should be the answer.

Explanation: Its not speed because speed can be constant, its not velocity because velocity can be constant as well. Plus velocity is just speed with direction. And its not inertia because inertia is an objects capacity to maintain its state of motion (at rest or in uniform motion)

Hope this helps! :)

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.