Velocity is a measure of an object's speed and direction of motion. It is a vector quantity, meaning it has both magnitude (speed) and direction (positive or negative). The unit of velocity is meters per second (m/s) in the International System of Units (SI).
Velocity and speed are often used interchangeably, but they are not the same. While speed only refers to the rate of motion, velocity also takes into account the direction of motion. For example, if a car is traveling at a speed of 60 mph in a northward direction, its velocity would be 60 mph north.
Acceleration is the rate at which an object's velocity changes over time. In other words, it is the change in velocity divided by the change in time. The direction of acceleration is determined by the direction of the change in velocity. If an object's velocity is increasing, its acceleration is positive. If its velocity is decreasing, its acceleration is negative.
Position, velocity, and time are all important factors in describing an object's motion. Position refers to the location of an object in space, velocity describes how fast and in what direction an object is moving, and time measures the duration of the motion. Together, these quantities can be used to calculate an object's displacement (change in position) and its average velocity.
No, if an object has a constant velocity, it means it is moving at a constant speed in a constant direction. This would result in a straight-line motion. If an object's position is changing, its velocity must also be changing, either in speed, direction, or both.