Here's why:
* Acceleration is the rate of change of velocity. It tells you how quickly an object's velocity is changing.
* Mass is the amount of matter in an object. It doesn't directly tell you about changes in motion.
* Velocity is the speed and direction of an object. It tells you where the object is going, but not how quickly its motion is changing.
To calculate acceleration, you need:
1. Initial velocity (v₁): The velocity of the object at the beginning of the time interval.
2. Final velocity (v₂): The velocity of the object at the end of the time interval.
3. Time interval (Δt): The amount of time over which the velocity changed.
Formula for acceleration:
```
acceleration (a) = (final velocity (v₂) - initial velocity (v₁)) / time interval (Δt)
```
Example:
A car starts at rest (v₁ = 0 m/s) and accelerates to a final velocity of 20 m/s in 5 seconds (Δt = 5 s). What is the car's acceleration?
```
a = (20 m/s - 0 m/s) / 5 s
a = 4 m/s²
```
Therefore, the car's acceleration is 4 meters per second squared.
