1) The lesson introduces concepts of force, motion, acceleration and deceleration. It defines acceleration as the rate of change of velocity over time. 2) Students are asked to work in groups to plot graphs of velocity versus time using example acceleration and deceleration scenarios. 3) The objective is for students to learn the definition and equation for acceleration, where acceleration equals the change in velocity over the time taken for that change.

1. Welcome to Physics lesson… FORCE AND MOTION Chapter 2 Prepared by Gayah Normahzura Bt Khaizan

2. Observe the animations below.. 1 2

3.  1 t = 0 v = 0 v = The car is…. t = 2 s t s = 0 s = 50 m

4.  2 t t = 0 v = 30m/s t = 3 s v = 0 The car is…. s = 0 s = 50 m

5. The objective of today’s lesson is: Define acceleration and deceleration and state that : a = v – u t

6. Previous Lesson.. Distance and displacement Speed and velocity Average speed, Average velocity, The SI unit for speed and velocity is __ __. v = ? v = ?

7. Previous Lesson.. Distance and displacement Speed and velocity Average speed, Average velocity, The SI unit for speed and velocity is m/s. v = s t v = s t

8. What will you learn now? Acceleration and deceleration Definition Equation

9. Activity…

10. Instruction.. Discuss in group A car accelerates from rest to 15m/s in 15 s. Plot a graph of velocity versus time with given information. Q1 15 15 10 10 5 5 0 0 Velocity, v (m/s) Time, t (s)

11. v = 0 v = 15m/s Time & Velocity change Time, t increase Velocity, v increase m/s (s) 15 15 10 10 5 5 0 0 Velocity, v (m/s) Time, t (s)

12. Definition Acceleration  is defined as the rate of change of velocity. The units for acceleration is m/s² Equation Acceleration= change of velocity time taken for the change a = v - u t

13. Instruction.. Discuss in group Plot a graph of velocity versus time with given information Q2 0 6 2 4 4 2 6 0 Velocity, v (m/s) Time, t (s)

14. v = 6m/s v = 0 m/s (s) 0 6 2 4 4 2 6 0 Velocity, v (m/s) Time, t (s)

15. a = v – u t v u a t

16. a  acceleration v u t  Final velocity  Initial velocity  Final velocity

17. EXERCISE (1) An object moves from rest with a uniform acceleration of 2 ms -2 .What is the velocity of the object after 30 s?

18. Answer….. Solution… u = 0 t = 30 s a = 2 ms -2 a = v- u t v = u + at = o + (2 x 30) = 60 ms -1

19. (2) A car increases its velocity steadily from 72 km h -1 to 108km h -1 in 5 s. What is its acceleration in ms -2 ?

20. Answer…… Solution….. u = 72km h -1 v = 108 km h -1 = 72 x 1 000 = 108 x 1 000 m s -1 60 x 60 60 x 60 = 20 m s -1 = 30 m s -1 t = 5 s Acceleration, a = v – u = 30 - 20 m s -1 t 5 = 2 m s -2 m s -1