Acceleration

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Basic concepts

Acceleration is the rate of change in velocity. In the equation below $a$ is the velocity.

$$\begin{array}{rl}a& =\frac{\Delta v}{\Delta t}\\ \Delta v& =\text{Change in velocity}\\ \Delta t& =\text{Change in time}\end{array}$$

Acceleration can be positive or negative, depending on whether the object is speeding up or slowing down.

Example

Lets say a object goes from 0 m/s to 20 m/s in 5 seconds, we can calculate the acceleration as follows:

$$\begin{array}{rl}\Delta v& =20-0=20\text{ m/s}\\ \Delta t& =5\text{ s}\\ a& =\frac{20}{5}=4{\text{ m/s}}^2\end{array}$$

Acceleration on time graphs

On a time graph acceleration would be written as $\text{acceleration}=\text{gradient of velocity}-\text{time graph}$ and is not much different from this distance time graph

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See also

• Distance and speed

References

• A Level Physics OCR (Pages 27-28) BOOK