Acceleration vs Retardation — Difference (with Table & FAQs)
Acceleration vs Retardation compared side by side — a 6-row comparison table, 4 key points and 3 exam FAQs. Class 9 Physics, free and no sign-up.
TL;DR: Acceleration vs Retardation compared side by side — a 6-row comparison table, 4 key points and 3 exam FAQs. Class 9 Physics, free and no sign-up.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
The main difference between Acceleration and Retardation: Acceleration is the rate of change of velocity in the direction of motion, while retardation is the rate of change of velocity opposite to the direction of
Acceleration vs Retardation — Comparison Table
| Basis | Acceleration | Retardation |
|---|---|---|
| Definition | Rate of increase of velocity | Rate of decrease of velocity |
| Direction | In the direction of motion | Opposite to the direction of motion |
| Sign | Positive acceleration | Negative acceleration |
| Effect on Speed | Speed increases with time | Speed decreases with time |
| Example | A car pressing the accelerator pedal increases speed | A car pressing the brake pedal decreases speed |
| SI Unit | Meter per second squared (m/s2) | Meter per second squared (m/s2) with negative value |
Key Points
- Retardation is negative acceleration, occurring when velocity decreases with time
- Both acceleration and retardation are rates of change of velocity but in opposite directions
- Acceleration increases kinetic energy while retardation decreases kinetic energy
- In equations of motion, retardation is represented as -a where a is a positive value
Frequently Asked Questions
What is the difference between acceleration and retardation?
Acceleration is the rate of change of velocity with time. Retardation, also called deceleration, is acceleration that acts against the motion and so reduces the speed — it is simply negative acceleration.
Is retardation a separate quantity from acceleration?
No. It is the same quantity with the opposite sign relative to the direction of motion. Both are measured in metres per second squared.
Can an object accelerate without changing speed?
Yes. Velocity includes direction, so an object moving in a circle at constant speed is accelerating, because its direction is changing continuously.