## Speed

9.1  Speed

 Definition The rate at which something moves or operates.

Speed as a rate:

 Definition It is the rate of change of distance with time.

Formula

$$\text{Speed} = \dfrac{\text{Distance}}{\text{Time}}$$

Uniform and non-uniform speed:

 Uniform Speed Non-uniform Speed Covers at equal distance in equal interval of time It implies the movement of an object along a straight line with steady speed Similar to the actual speed of the object. The distance-time graph shows a straight line Covers at unequal distance in equal interval of time It implies the movement of an object along a straight line with variable speed Different from the actual speed of the object The distance-time graph shows a curved line

Average speed:

Formula

$$\text{Average speed} = \dfrac{\text{Total distance}}{\text{Total time}}$$

 Example A truck travels $$132\text{ km}$$ in $$22\text{ hours}$$. What is the speed of the truck? Answer:  We’re looking for speed, the distance should be divided by time.  \begin{aligned} \space \text{Speed}&= \dfrac{\text{Distance}}{\text{Time}} \\\\& = \dfrac{132 \space\text{km}}{22 \space \text{h}} \\\\&= 6 \space \text{km/h}. \end{aligned}