1. KINEMATICS The Study of How Objects Move

2. Displacement vs. Distance Consider a a turtle on a highway. 0246810 He starts at 2km.

3. Displacement vs. Distance Consider a a turtle on a highway. 0246810 Then walks to the 10km line.

4. Displacement vs. Distance Consider a a turtle on a highway. 0246810 Finally, he goes back to the 8km mark. What was the total distance he traveled?

5. Displacement vs. Distance continued The turtle’s total distance is how far he actually moved (p21)  8m + 2m = 10m distance The turtles total displacement is how far he ended up from his starting point or the change in position: and is (add) measured from a reference point

6. Scalar vs Vector (p 21 margin) A scalar quantity has magnitude only. Distance and speed are scalar quantities (p 21margin) A vector quantity has direction as well as magnitude Displacement, velocity and acceleration are vector quantities

7. Displacement vs. Distance continued The turtle’s total distance is how far he actually went and is a SCALAR quantity  8m + 2m = 10m distance The turtle’s total displacement is how far he ended up from his starting point! Since displacement includes a direction it is a VECTOR quantity to the right

8. (add to margin of p 21) Two more distance vs displacement examples:

9. Speed Speed is a scalar quantity, it has no direction. (p 21) Speed is the magnitude of velocity Speed is the distance moved divided by the time or

10. (add to p 21) only use When object is already moving When there is no starting, stopping or dropping This formula will give average speed if d = distance This formula will produce velocity if d = displacement See examples on p 26

11. Speed If a chicken runs 60m across a road in 3 seconds, how fast is it running?

12. Speed If a chicken runs 60m across a road in 3 seconds, how fast is it running?

13. Speed If a chicken runs 60m across a road in 3 seconds, how fast is it running?

14. Velocity Velocity describes speed AND direction (it’s a vector quantity) (p21)It is the rate of change in an object’s position or

15. Velocity A warthog runs north across the road 60m in 3 seconds, what is its velocity?

16. Velocity A warthog runs north across the road 60m in 3 seconds, what is its velocity?

17. Velocity A warthog runs north across the road 60m in 3 seconds, what is its velocity?

18. (add to bottom margin p21) direction can be: N, S, E, W, left, right, up, down, + or – Speeds: 10m/s5.0 km/h Velocities:10m/s, N-5.0 km/h In physics a negative sign can mean: a. less than zero b. to the left c. down and you must decide which of these makes sense in the question

19. Average and Instantaneous Speed/Velocity (p 24) average velocity and speed does not give use any information on how fast an object is moving at any given time Instantaneous velocity and instantaneous speed is the velocity or speed at some instant in time.

20. Average velocity Time (s) Distance (m) We can also find average velocity on a curved graph.

21. Average velocity Time (s) Distance (m) To find average velocity on a curve, you need to find two points on the graph and join them with a line.

22. Average velocity Time (s) Distance (m) To find average velocity on a curve, you need to find two points on the graph and join them with a line.

23. Average velocity Time (s) Distance (m) To find average velocity on a curve, you need to find two points on the graph and join them with a line.

24. Average velocity Time (s) Distance (m) To find average velocity on a curve, you need to find two points on the graph and join them with a line.

25. Average velocity Time (s) Distance (m) Next, create a slope triangle.

26. Average velocity Time (s) Distance (m) Next, create a slope triangle.

27. Average velocity Time (s) Distance (m) Next, create a slope triangle.

28. Average velocity Time (s) Distance (m) Next, create a slope triangle.

29. Average velocity Time (s) Distance (m) Next, create a slope triangle.

30. Average velocity Time (s) Distance (m) *Average velocity is equal to the slope of the line joined at 2 points.

31. Average velocity Time (s) Distance (m) *Average velocity is equal to the slope of the line joined at 2 points.

32. Instantaneous Velocity This is the velocity we find at a single point in time. Ex. If there is a car crash, what was the velocity at the instant that the collision occurs? Consider the following curve.

33. Distance (m) Time (s) Its not linear To determine a velocity at a single point, we must determine the slope of a line at that one point. (see p38)

34. Distance (m) Time (s) Since we can’t take the slope of a curve, we need to draw a special type of line that intersects at one point.

35. Distance (m) Time (s) This is a tangent line

36. Distance (m) Time (s) This is a tangent line A tangent line should just touch the graph at a single point It should not cross the curve. Once we have the tangent we can find the slope of the line.

37. Distance (m) Time (s) *After we have drawn the tangent line, we simply create a slope triangle.

38. Distance (m) Time (s) *After we have drawn the tangent line, we simply create a slope triangle.

39. Distance (m) Time (s) *After we have drawn the tangent line, we simply create a slope triangle.

40. Distance (m) Time (s) *This slope will give us the instantaneous velocity.