Acceleration

This lesson covers acceleration, velocity-time graphs, and the kinematic equation v² = u² + 2as — as required by the Edexcel GCSE Physics specification (1PH0), Topic 1: Key Concepts of Physics. You need to be able to calculate acceleration, interpret velocity-time graphs, and apply the kinematic equation (Higher tier).

---

What Is Acceleration?

Acceleration is the rate of change of velocity. It tells you how quickly an object's velocity is changing.

acceleration = change in velocity ÷ time taken

$a = \frac{\Delta v}{t} = \frac{v - u}{t}$a=tΔv​=tv−u​

Where:

• a = acceleration (m/s²)
• v = final velocity (m/s)
• u = initial velocity (m/s)
• t = time taken (s)
• Δv = change in velocity = v − u

Key Points

• Acceleration is a vector quantity — it has both magnitude and direction.
• The SI unit of acceleration is metres per second squared (m/s²).
• A positive acceleration means the object is speeding up (in the direction of travel).
• A negative acceleration (deceleration) means the object is slowing down.