The speed and velocity of an object are equal when the object is moving in a straight line with a constant speed and in a single direction. In such cases, the velocity is defined as the speed of the object along with its direction of motion. When the object moves in a straight line without changing its speed or direction, the magnitude of the velocity (which is the speed) will be equal to the speed of the object. However, if the object changes its direction, even while maintaining a constant speed, the velocity will differ from the speed, as velocity takes into account the object's direction of motion.