The rate at which velocity changes with time is known as acceleration.
Understanding Acceleration
Acceleration is a fundamental concept in physics that describes how the velocity of an object changes over a period of time. Velocity is not just about how fast something is moving (speed), but also the direction in which it is moving. Therefore, a change in velocity can mean a change in speed, a change in direction, or both.
As defined, acceleration is the "rate at which velocity changes with time, in terms of both speed and direction." This means an object is considered to be accelerating if:
- Its speed increases.
- Its speed decreases (often called deceleration, but still a form of acceleration).
- Its direction of motion changes, even if its speed remains constant.
Examples of Acceleration
Here are some common examples illustrating different types of acceleration:
- Speeding Up: A car starting from rest and increasing its speed on a straight road.
- Slowing Down: A cyclist applying brakes to come to a stop.
- Changing Direction: A satellite orbiting the Earth at a constant speed is continuously accelerating because its direction of motion is always changing.
- Combined Changes: A roller coaster speeding up as it descends a curved track involves changes in both speed and direction, resulting in acceleration.
In essence, acceleration is a measure of how quickly an object's state of motion (its velocity) is changing.
