**6.1 Quantity Represented by the Gradient of a Graph**

The gradient of graph is the rate of change of a quantity on the vertical axis with respect to the change of another quantity on the horizontal axis.

**(A) Distance – Time Graph**

**1.**The gradient of a distance-time graph is speed.

**2.**

**(a)**From

*O*to

*P*: Gradient = positive

**(b)**From

*P*to

*Q*: Gradient = 0 → (The object stopped moving)

**Example 1:**

The diagram above shows a graph of distance-time for the motion of a car. Find the speed of the car for the first 6 second.

*Solution:*The speed of the car for the first 6 seconds

= Gradient

$\begin{array}{l}=\frac{12-0}{6-0}\\ =2.0{\text{ms}}^{-1}\end{array}$