1. A reminder

2. No movement
speed
time
distance
time

3. Constant speed
speed
time
distance
time
Area = distance travelled

4. Constant acceleration
speed
time
Gradient = acceleration
a = (v-u)/t
distance
time
Area = distance travelled

5. Today’s lesson Define displacement, velocity, speed and acceleration
Explain the difference between instantaneous and average values of speed, velocity and acceleration

6. Displacement

7. Displacement
Displacement the distance moved in a stated direction (the distance and direction from the starting point). A VECTOR

8. Displacement/time graphs
Usually in 1 dimension (+ = forward and - = backwards)
Displacement/m
Time/s

9. Velocity?

10. Velocity?
Velocity is the rate of change of displacement. Also a VECTOR

11. Velocity/time graphs
Usually in 1 dimension (+ = forward and - = backwards)
Ball being thrown into the air, gradient = constant = m.s-2
velocity/m.s-1
Time/s

12. Acceleration?

13. Acceleration?
Acceleration is the rate of change of velocity. Also a VECTOR

14. An interesting example
Think of a dog (dead) orbiting the earth with constant speed (in a circle). 14

15. An interesting example
At this point, what is its velocity?
velocity? 15

16. An interesting example
velocity 16

17. An interesting example
What is its velocity here?
velocity? 17

18. An interesting example
As you can see the velocity has changed as it is now going in another direction.
velocity 18

19. An interesting example
We have constant speed but changing velocity.
velocity 19

20. An interesting example
We have constant speed but changing velocity.
Of course a changing velocity means it must be accelerating!
velocity 20

21. Acceleration/time graphs
Usually in 1 dimension (+ = up and - = down)
Acceleration = constant = m.s-2
accel/m.s-2
Time/s

22. Average speed/velocity?

23. Average speed/velocity?
Average speed/velocity is change in distance/displacement divided by time taken over a period of time.

24. Instantaneous speed/velocity?

25. Instantaneous speed/velocity?
Instantaneous speed/velocity is the change in distance/displacement divided by time at one particular time.