| English | Acceleration |
|---|---|
| Bahasa Melayu | Pecutan |
| 中文 | 加速度 |
Definition
The rate of change of velocity with time; a vector quantity measured in metres per second squared (m s⁻²).
In exam terms
Acceleration is the rate of change of velocity with time. It is a vector, symbol a, SI unit the metre per second squared (m s⁻²), given by acceleration = (final velocity − initial velocity) ÷ time, or a = (v − u) ÷ t.
For example, if a car speeds up from 4 m s⁻¹ to 20 m s⁻¹ in 8 s, then a = (20 m s⁻¹ − 4 m s⁻¹) ÷ 8 s = 2 m s⁻². A negative value means the object is slowing down (deceleration), where velocity decreases with time.
Do not confuse it with velocity
Do not confuse acceleration with velocity. Velocity is how fast the position changes; acceleration is how fast the velocity changes.
An object can move at a very high constant velocity yet have zero acceleration, because its velocity is not changing at all.
In Paper 2 you may be asked to calculate the acceleration from a velocity-time graph, where acceleration is the gradient of the line, so use the change in velocity over the time taken, not the velocity value itself.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)