Final answer:
The car's velocity is 40 km/h in the stated direction. Velocity includes both speed and direction, making it different from speed, which is directionless.
Step-by-step explanation:
If a car travels 40 km in one direction in an hour, its velocity is 40 km/h in that direction. Velocity is a vector quantity, which means it includes both magnitude and direction. The magnitude of the velocity in this case is 40 km/h, since that's the speed at which the car is traveling. Given that the direction is specified (in one direction), it is part of the velocity description. Therefore, the car's velocity is 40 km/h in the specified direction. If, for instance, it's mentioned that the direction is north, then the velocity is 40 km/h north.
It is important to distinguish between speed and velocity. Speed is a scalar quantity that describes how fast an object is moving without any direction, while velocity also includes direction. For example, a car moving in a circle at a constant speed of 40 km/h actually has a changing velocity because its direction changes continuously.