When a vehicle slows down or an object reduces speed, it’s experiencing deceleration—the opposite of acceleration. Whether you’re driving, biking, or observing objects in motion, knowing how to calculate deceleration can be helpful in science, engineering, and daily life.
Table of Contents
🚗 What is Deceleration?
Deceleration is the rate at which an object slows down. It’s just like acceleration, but the velocity is decreasing instead of increasing.
Think of it like this: If you’re driving at 60 km/h and you slow down to 20 km/h in 5 seconds, you’re decelerating.
📏 The Formula
To calculate deceleration, use this formula:
Deceleration = (Initial Velocity – Final Velocity) / Time
Where:
- Initial Velocity (Vi) is the speed at the start
- Final Velocity (Vf) is the speed at the end
- Time (t) is how long the change takes
- Result is usually in meters per second squared (m/s²)
📉 Example
Let’s say a skateboarder is moving at 10 m/s and comes to a stop (0 m/s) in 5 seconds.
Deceleration = (10 – 0) / 5 = 2 m/s²
That means the skateboarder slows down at a rate of 2 meters per second squared.
📌 Key Notes
- Deceleration is always a positive value, but it’s understood to mean a reduction in speed.
- If an object is coming to a stop, its final velocity is 0.
- Use consistent units—if velocity is in m/s, time must be in seconds.
🎯 Quick Tips
- If your result is negative, it’s likely just acceleration in the opposite direction.
- Use this formula in physics problems, car safety studies, or even sports analysis.