大象传媒

Rate of change of speed

When speed changes, the rate of change of speed can be calculated using the equation:

rate of change of speed = \(\frac{\text{final speed 鈥 initial speed}}{\text{time taken}}\)

Rate of change of speed is a quantity and it is measured in m/s2.

Speed-time graphs

Speed-time graphs show how the speed of a moving object changes with time.

Summary

Speed 鈥 Time Graph
Gradient of graphRate of Change of Speed (m/s2)
Area under graphDistance (m)
Gradient of graph
Speed 鈥 Time GraphRate of Change of Speed (m/s2)
Area under graph
Speed 鈥 Time GraphDistance (m)

Example

A speed-time graph for a car moving between two sets of traffic lights

This is a speed-time graph for a car moving between two sets of traffic lights.

Question

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

Question

What is the rate of change of speed of the car between 20 s and 25 s?

Question

What is the total distance between the two sets of traffic lights?

Question

What is the average speed of the car between the traffic lights?

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