Acceleration is the rate at which an object’s velocity changes over time. It is a vector quantity, meaning it has both magnitude and direction. Acceleration occurs when an object speeds up, slows down, or changes direction.
Formula for Acceleration:
Where:
- a = acceleration
- Δv = change in velocity (final velocity – initial velocity)
- Δt = time taken for the velocity change
Key Points to remember about Acceleration:
- SI Unit: The standard unit of acceleration is meters per second squared (m/s²).
- Positive Acceleration: When an object speeds up, the acceleration is in the direction of its velocity.
- Negative Acceleration (Deceleration): When an object slows down, the acceleration is in the opposite direction to its velocity.
- Uniform Acceleration: If the velocity of an object changes by an equal amount in every time interval, it is said to have uniform acceleration.
Example:
- Speeding Up: A car increases its velocity from 20 m/s to 30 m/s in 5 seconds. The acceleration can be calculated as:
Slowing Down (Deceleration): If a bike is moving at 15 m/s and comes to a stop in 3 seconds, the acceleration (which is negative in this case) would be:
Types of Acceleration:
- Uniform Acceleration: When acceleration remains constant over time, such as in free fall under gravity.
- Non-uniform Acceleration: When acceleration changes over time, such as a car accelerating unevenly in traffic.
In essence, acceleration tells you how quickly and in which direction an object’s velocity is changing.