1. Review Homework

4. P2 – Forces and Motion Lesson 2: D-T and V-T Graphs

5. Lesson Objectives To be able to draw and use a Distance- Time graph To be able to draw and use a Velocity- Time graph To be able to calculate acceleration and speed using graphs.

6. Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration. 1. A ferrari was travelling at 20 m/s behind a lorry. It pulled out to overtake and accelerated at 4 m/s 2 for 2 seconds. What was its new speed ? New Speed = Old Speed + Change in Speed = 20 m/s + 8 m/s = 28 m/s  v v t a

7. You can draw a graph to show how an object travels. Lets plot one together Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

8. Distance-Time Graphs A family travel by car from London to Manchester and their journey is shown below. The family stop in Birmingham for lunch for 1 hour and in Lymm to collect friends for 1 hour. JourneyDistance (miles)Time (hours) London to Birmingham1202:30 Birmingham to Lymm751:30 Lymm to Manchester150:30 Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

9. JourneyDistance (miles) Time (hours) London to Birmingham 120 (120) 2:30 (2:30) Break0 (120) 1:00 (3.30) Birmingham to Lymm 75 (195) 1:30 (5:00) Break0 (195) 1:00 (6:00) Lymm to Manchester 15 (210) 0:30 (6:30) Time (hours) Displaement (miles) Displacement time graph to show a journey from London to Manchester 0 1 2 3 4 5 6 7 075150225 xx xx x Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

10. Time (hours) Displacement (miles) Displacment time graph to show a journey from London to Manchester 0 1 2 3 4 5 6 7 075150225 xx xx x Stationary for lunch in Birmingham Stationary in Lymm Arrive in Manchester Leave London – then travel at constant speed Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

11. Important things to know: The gradient = speed Flat section are where it’s stopped The steeper the slope, the faster it is going Downhill sections means that it’s going towards its starting point. Curves represent acceleration A steepening curve means it’s speeding up A leaving off curve means it’s slowing down Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

12. Calculating Speed You can use a distance-time graph to calculate the speed. All you need to do is work out the gradient. Gradient = Vertical Horizontal Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration. Time (hours) Distance (miles) 0 1 2 3 4 5 075150 x e.g. 150 5 = 30 mph (Remember to use the units on the axis)

13. Are you now able to…. I still feel unsure. I need some more help to understand. I feel ok. I need to do some more work to check my understanding. I am happy and feel I understand and can explain the main points. To be able to draw and use a Distance- Time graph To be able to draw and use a Velocity- Time graph To be able to calculate acceleration and speed using graphs. Keywords: Distance-Time, Velocity-Time, Gradient,

14. P2 – Forces and Motion Lesson 3: D-T and V-T Graphs 2

15. Lesson Objectives To be able to draw and use a Distance- Time graph To be able to draw and use a Velocity- Time graph To be able to calculate acceleration and speed using graphs.

16. Another graph that can be plotted is a velocity- time graph. Lets plot one together Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

17. Velocity-Time Graphs 1.A car accelerates to 30mph in 20s. 2.Car travels at 30mph for 40s 3.The car then decelerates to 10mph in 20s 4.The car then travels at 10mph for 30s. 5.The car then comes to a stop in 10s. Draw a V-T of the journey. Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

18. Velocity-Time Graphs – Questions…. 1.What is the cars acceleration in the first 20s? 2.How far did the car travel when it travelled at a constant speed of 30m/s? Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

19. Time (s) Average Speed (mph) Velocity-Time graph 0 30 60 90 110 140 0102030 x Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration. Velocity-Time Graphs 1.A car accelerates to 30mph in 20s. 2.Car travels at 30mph for 40s (60s) 3.The car then decelerates to 10mph in 20s (80s) 4.The car then travels at 10mph for 30s (110s). 5.The car then comes to a stop in 10s (120s). Draw a V-T of the journey. x xx xx

20. Time (s) Average Speed (mph) Velocity-Time graph 0 30 60 90 110 140 0102030 x Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration. Acceleration at from 0 to 30? x xx xx a = change in v time taken Therefore acceleration is the gradient: 30 = 1.5 m/s 2 20

21. Time (s) Average Speed (mph) Velocity-Time graph 0 30 60 90 110 140 0102030 x Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration. Velocity-Time Graphs How far has he travelled when at a constant speed of 30mph? Area = distance travelled. x xx xx Area = length x width 30mph x 40s = Area 120 miles

22. Important things to know: The gradient = acceleration Flat section are travelling at a steady speed The steeper the slope, the greater the acceleration. Uphill sections are acceleration. Downhill section are deceleration The area under any section is the distance travelled in that time interval. A curve means a changing acceleration. Keywords: Distance-Time, Velocity-Time, Gradient, To know the difference between speed and velocity. To be able to calculate speed. To be able to calculate acceleration.

23. Velocity/TimeDistance/Time Stopped Const’ Velocity Const’ Accel’n D t D t D t V t V t V t Gradient = Velocity Gradient = Accel’n Area = Distance travelled

24. Are you now able to…. I still feel unsure. I need some more help to understand. I feel ok. I need to do some more work to check my understanding. I am happy and feel I understand and can explain the main points. To be able to draw and use a Distance- Time graph To be able to draw and use a Velocity- Time graph To be able to calculate acceleration and speed using graphs. Keywords: Distance-Time, Velocity-Time, Gradient,