Can you put these items in order of their top speeds? Distance–time graphs 20 April 2017 Can you put these items in order of their top speeds? Formula 1 car Jet fighter Human Laser beam Snail Cheetah Tortoise

Can you put these items in order of their top speeds? Distance–time graphs 20 April 2017 Can you put these items in order of their top speeds? Snail 2 mm/s Tortoise 5 cm/s Human 12 m/s Cheetah 34 m/s Formula 1 car 100 m/s Jet fighter 700 m/s Laser beam 300 000 000 m/s

Distance–time graphs How can a d-t graph show: 20 April 2017 How can a d-t graph show: something is stationary? Moving at a constant speed How can we calculate average speed? The Eurostar train runs on the UK’s only high speed rail line. It can reach a maximum speed of 186mph. London to Paris takes 2 hours 15 mins a distance of 211miles.

Looking at graphs Which graph shows a stationary object? Distance (metres) Distance (metres) Time (sec) Time (sec) Which graph shows a stationary object? Which graph shows an object moving at constant speed?

Looking at graphs Distance (metres) Distance (metres) Time (sec) Time (sec) Constant speed – same change in distance every second. Stationary – no change in distance

Describe this journey in as much detail as you can. Distance (metres) Speed = distance time 100 50 C B A 0 10 20 30 40 50 60 Time (sec) What was the speed at A, B and C? What was the average speed?

Measuring speed Speed = distance ÷ time No. of books Distance (m) Set up the equipment as shown. Measure and mark a distance down the ramp. Measure the time to roll down the slope. Speed = distance ÷ time Diagram Trolley Books ramp No. of books Distance (m) Time (s) Speed (m/s) 1 2 3 4 5

Summary The steeper the line on a distance time graph the greater the speed. Speed = distance travelled (m) (m/s) time (s)