# Kinematic Concepts - Mission KC4 Detailed Help

 If an object has an acceleration then it MUST be ____. List all that apply ... .
 Definition of Acceleration: The acceleration of an object is the rate at which the object changes its velocity.
 Accelerating objects are changing their velocity. Velocity is often thought of as an object's speed with a direction. Thus, objects that are accelerating are either speeding up, slowing down or changing directions. Changing the velocity in any one of these three ways would be an example of an accelerated motion. Objects that are NOT accelerating are obviously not changing their velocity. Such objects have a constant velocity value. Neither their speed nor their direction is changing. The object could be at rest and maintaining a constant velocity of 0 m/s. Or the object could be moving in a straight line with a constant speed value.
 The use of the word MUST in this question is not trivial. Its use makes the question different than saying Which of the following are examples of acceleration? or Which objects could be accelerating?