Distance / time graphs

Lesson aims To show speed as a graph. To identify graphs showing constant and changing speed. To calculate speed, distance and time at points on a graph.

No movement? distance Ask a student to sketch on whiteboard. time

No movement distance time

Constant speed? distance Ask a student to sketch on whiteboard. time

Constant speed distance time

Constant speed How would the graph look different for a faster constant speed (walking to Science)? distance Ask a student to sketch on whiteboard. time

Constant speed fast distance time

Constant speed fast How would the graph look different for a slower constant speed (walking to any class but Science)? distance Ask a student to sketch on whiteboard. time

Constant speed fast distance slow time

The gradient of the graph gives the speed Constant speed fast The gradient of the graph gives the speed distance slow time

Getting faster? (accelerating) distance Ask a student to sketch on whiteboard. time

Getting faster (accelerating) distance time

Examples distance time

A car accelerating from stop and then hitting a wall distance Ask a student to sketch on whiteboard. time

A car accelerating from stop and then hitting a wall distance time

How far had the object gone after 20 seconds? 40 30 Distance (metres) Distance (m) 20 10 Time/s 20 40 60 80 100 Time (s) How far had the object gone after 20 seconds? How far had the object gone after 60 seconds? When is the object standing still? When was the object traveling the fastest?

A man left home at 12 noon to go for a cycle ride A man left home at 12 noon to go for a cycle ride. The travel graph represents part of the man’s journey. For how many minutes did he rest? 2. Find his distance from home at 1.30pm. 15 minutes 15 km

What is happening between 9AM and 11AM? Constant speed   What is happening between 9AM and 11AM? 2. What do you think bicyclist is doing between 11AM and 1PM? 3. What was the total distance covered from 11AM to 4PM? Constant speed Stopped to rest 30 miles

Distance-time graphs 2) Horizontal line = 40 30 20 10 4) Diagonal line downwards = Returning to start No movement Distance (metres) 3) Steeper diagonal line = Time/s Diagonal line = 20 40 60 80 100 Constant speed Faster constant speed

Work to be done today Worksheet – distance / time graphs Make up a distance / time graph to show a journey you could make. (It doesn’t have to be on foot). Write about what is happening at each stage of the journey.