Final answer:
To report the velocity of an object, both its speed and direction must be specified, distinguishing velocity from speed, which is scalar and only indicates magnitude.
Step-by-step explanation:
To report the velocity of an object, we must specify both its speed and its direction. Velocity is a vector quantity, which means it includes both magnitude (how fast the object is moving) and direction (where it's moving to). In contrast, speed is a scalar quantity; it only describes how fast an object is moving without regard to its direction. Understanding this concept is crucial in physics because it describes the motion of an object more completely than speed alone.
When looking at a velocity vs. time graph, we can determine an object's acceleration, infer the direction of motion, and understand the motion within a certain reference frame. The slope of a position vs. time graph can help us calculate velocity as well. For example, if the slope is positive, the velocity is positive, indicating motion in the positive direction. Conversely, a negative slope indicates a negative velocity and motion in the opposite direction.
The velocity of an object can be expressed with statements like '20 kilometers per hour due south', where 'due south' describes the direction, giving us more information than if we were to say '20 kilometers per hour' alone, which only describes speed.