On a distance-time graph, the gradient of the graph gives the **velocity** of the object being measured:

velocity = `frac(text(distance))(text(time))`

From the distance-time graph, above, what is the velocity of the car at 5 seconds? Give your answer correct to 1 decimal place.

The velocity is the gradient = `frac(text(change in distance))(text(change in time))`

Take a tangent at 5 seconds

Gradient of tangent

= `frac(52.5 - 37)(7 - 3)`

= 3.875 ms^{-1}

Answer: 3.9 ms^{-1}

Using the graph, what is the average velocity for the first 100m? Give your answer correct to 1 decimal place.

Distance covered in 100m took 9 seconds

= `frac(100)(9)`

= 11.11 ms^{-1}

Answer: 11.1 ms^{-1}

See also Kinematic Graphs

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