1. Dynamics and Space Acceleration

2. Learning Outcomes Acceleration of a vehicle between two points using appropriate relationships with initial and final velocity and time of change. Acceleration from a velocity time graph.

3. Lesson 1 Define the term acceleration. Carry out an experiment to determine the acceleration of a trolley.

4. Acceleration Intro Have you ever heard a phrase used to describe how quick a car is? It can do 0 – 60 in 3 seconds. This is an example of a cars acceleration

5. Acceleration Name of Car Time to accelerate from 0-27m/s (s) Micra15.2 Focus12.9 Corsa19.9 Ka13.7 Smart car19.6 Mondeo13.0 Questions to consider: 1.Which car takes the shortest time to speed up to 27 m/s? 2.Which car has the fastest acceleration? Why? 3.Which car takes the longest time to speed up to 27 m/s? 4.Which car has the slowest acceleration? Why?

6. Acceleration An acceleration is defined as “the change in velocity per unit time”. It is the change in velocity of a body over a certain time period.

7. Acceleration Acceleration, (a), can be calculated by subtracting the initial velocity, (u), from the final velocity (v), of a body over a certain period of time, (t). a=v – u t Acceleration has the unit m/s 2 It is a vector quantity.

8. Experiment to Measure Acceleration

9. Results QuantityValue t 1, time to pass light gate 1 s t 2, time to pass light gate 2 s t 3, time to travel between light gates s d, card length m u, initial velocity (d / t 1 ) m/s u, final velocity (d / t 2 ) m/s a, acceleration (v – u / t 3 ) m/s 2

10. Lesson 2 Carry out calculations for acceleration using the equation a = v – u. t State that deceleration is a negative acceleration. Calculate acceleration from a slope on a velocity-time graph.

11. Example 1 a = ? v = 27 m/s u = 0 m/s t = 19.9 s

12. Example 2 a = 20 m/s 2 v = 65 m/s u = 5 m/s t = ?

13. Example 3 a = 10 m/s 2 v = ? u = 10 m/s t = 5 s

14. Deceleration If a moving body has a ‘negative acceleration’ then it is decelerating. In other words it is slowing down.

15. Example a = ? v = 0 m/s u = 25 m/s t = 5 s

16. v-t graph example Using the v-t graph below for the motion of a car find: a)The initial acceleration b)The final acceleration a)a = v – u t = 10-0 4 = 2.5 m/s 2 b)a = v – u t = 0-10_ (10-8) = - 5 m/s 2 [note –ve sign for deceleration]

17. Velocity-Time Graphs Questions on displacement and acceleration

18. 2011

19. 2008

20. 2009

21. 2000, Qu: 21

22. 2003 Qu: 21

23. 2007 Qu: 21

24. 2010 Qu: 21

25. Summary Acceleration You should now be able to do the following: Determine the acceleration of a vehicle between two points using a = v-u. t Calculate the acceleration of a body from a slope on a velocity-time graph.