### GCSE Physics

Energy
Forces
Forces and Motion
Waves in Matter
Electricity
Magnetism and Electromagnetism
Particle Model of Matter
Atomic Structure
Space Physics

# Acceleration

Acceleration is the rate of change in the velocity, which is measured in metres per second squared (m/s2). When an object changes velocity, it accelerates.

• Acceleration indicates how quickly an object is speeding up. So, we can say that acceleration is the change in velocity over a period of time.

The equation to calculate the average acceleration is:

• a = Acceleration in metres per second squared (m/s2)
• Δv = Change in velocity in metres per second (m/s)
• t = time taken in seconds (s)

Δ is the delta symbol, which means change. So, Δv means change in velocity. This can also be written as v − u, in which v is the final velocity and u is the initial velocity. So by subtracting the initial velocity from the final velocity, we get the change in velocity.

Acceleration is a vector quantity, meaning it takes into account both magnitude and direction. Therefore, acceleration can be a negative number, indicating that an object is slowing down, also known as deceleration.

## Uniform Acceleration

If an object moves with uniform acceleration, it means that its velocity changes by the same amount during each equal time interval. In other words, the object’s speed is increasing at a constant rate. In this case, we can use this equation:

• v = Final velocity in metres per second (m/s)
• u = Initial velocity in metres per second (m/s)
• a = Acceleration in metres per second squared (m/s2)
• s = Distance in metres (m)

You might already be familiar with most of the symbols in this equation. However, this equation includes distance instead of time. You have to choose which equation to use based on the question. If the time taken is unknown, then it is likely that you will have to use this equation.

Also, note that if an object starts from a stationary position, its initial velocity is 0.

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