When speed transforms, the price of readjust of rate can be calculated utilizing the equation:

price of adjust of speed = (frac extfinal speed – initial speed exttime taken)

Rate of readjust of rate is a scalar amount and it is measured in m/s2.

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## Speed-time graphs

Speed-time graphs show just how the rate of a relocating object alters with time.

## Summary

Speed – Time Graph
Gradient of graphRate of Change of Speed (m/s2)
Area under graphDistance (m)

## Example

This is a speed-time graph for a auto relocating between 2 sets of traffic lights.

Question

What is the rate of change of rate of the vehicle between 0 s and 10 s?

Reveal answer
The price of readjust of speed is the slope or gradient of the speed-time graph

rate of change of rate = gradient of the speed-time graph

= (frac extfinal rate – initial speed exttime taken)

price of readjust of rate = (16 m/s – 0 m/s) ÷ 10 s = 1.6 m/s2

Question

What is the price of readjust of speed of the vehicle between 20 s and also 25 s?

Reveal answer
The rate of adjust of rate = gradient of the speed-time graph = (frac extfinal speed – initial speed exttime taken)

The price of change of speed = (0 m/s – 16 m/s) ÷ 5 s

= -3.2 m/s2.

The vehicle is slowing down at a rate of 3.2 m/s2.

Question

What is the full distance between the 2 sets of website traffic lights?

Reveal answer
The soimg.orgmplete distance in between the two sets of web traffic lights = the full location under the graph.

Tright here are 2 triangles and a rectangle. Find the location of each.

From 0 s – 10 s

distance travelled = area of the triangle = ½ x 10 s x 16 m/s = 80 m.

From 10 s – 20 s

distance took a trip = area of the rectangle = 10 s x 16 m/s = 160 m.

From 20 s – 25 s

distance took a trip = location of the triangle = ½ x 5 s x 16 m/s = 40 m.

Total distance travelled = 80 m + 160 m + 40 m = 280 m.

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Question

What is the average speed of the vehicle in between the traffic lights?

Reveal answer
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Median rate = (frac extfull distance moved exttime taken)

average speed = 280 m ÷ 25 s = 11.2 m/s.

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## More Guides

Distance-time graphs - CCEA

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