Brainlag PlusAcceleration as change in velocity per second, deceleration, and what the gradient and the area of a velocity-time graph give you.
Acceleration is change per second
Acceleration is how much the velocity changes every second.
acceleration = change in velocity ÷ time taken
a = (v − u) ÷ t
u is the starting velocity, v the final one. The unit is m/s² ("metres per second, per second"): an acceleration of 3 m/s² adds 3 m/s to the velocity every second.
Slowing down gives a negative acceleration. Questions often call it a deceleration and want the positive number: a car going from 20 m/s to rest in 4 s has a = −5 m/s², a deceleration of 5 m/s².
The rest of this lesson and its 7 practice questions are in Plus.
Screen 1 of 3, free to read.
- 7 exam-style questions, marked as you go, each with a worked solution
- The Forces and acceleration simulation beside every question
- Anything you get wrong is saved to your flashcards