Velocity and Speed (continued)
Speed describes how fast an object moves.
Velocity describes both the speed and direction in which an object moves.
Here the term ‘velocity’ tells us the speed and direction of the cars. Since one car is moving on a curved road, we must refer to its speed, because its velocity is always chaging. The car moving on the straight road has a constnat speed and a constant velocity. Speed is a common term in our daily life, and the term velocity is often used only if the object is confined to move in one particular direction.
This picture shows you how to think about velocity by using a position versus time graph. Here car-I has more velocity than car-II because car-I travels 1 km in a shorter time interval of 20 seconds as shown in the graph. The advantage of the graph is to identify that motion without doing any calculations.