3. Slides Minutes 1 927 2 Vectors 1339 3 Kinematics 1339 4 Graphs 1030 5 Energy 1030 6 Power 515 7 Springs 412 8 Shadows 39 9 Field of Vision 721 10 Colors 39 11 Concave mirrors 721 12 Convex mirrors 412 13 Refraction 515 14 Lenses 1030 15 Optical Power 618 Displacement

4. Free Body Diagrams A free body diagram is a pictorial representation of an object used to study the forces acting on a system. E x a m p l e A free body diagram shows only the information required by the problem under study.

5. Click Distance is a scalar. (It has no direction) Displacement is a vector. (It has direction) Displacement is the straight line directly from the starting point to the ending point. N O T E Click Starting point Displacement Ending point A o Remember: Displacement has magnitude and direction.

7. Click An object travels the following distances: 9 m [E], 6 m [N], 4 m [W] and 2 m [S] Which of the vectors on the right represents the displacement of the object? A) I B) II C) III D) IV Click Not drawn to scale 9 m [E] 6 m [N] 4 m [W] 2 m [S] Displacement II III I IV Displacement Slide:

8. A) 4.00 km North B) 4.00 km South C) 23.3 km North D) 23.3 km South E) 0 Click Riding her bike, Stefania traveled the following distance from point-A to point-D: AB = 4.00km North BC = 11.3 km [S 45 E] CD = 8.00 km West Determine Stefania’s displacement. Note BD = CD = 8.00 km and BA = AD = 4.00 km Displacement Slide:

9. The graph below represents the velocity of a butterfly as it flies across a field for 20 seconds. Click A) 365 m B) 325 m C) 185 m D) 145 m What is the displacement of the butterfly from the 4 th to the 20 th s? +235 m (forward) -90 m (backward) Displacement Slide:

10. To go from his house to four of his friends, James must travel in different directions as listed below: Ann: 4.8 km [N], 3.2 km [W] Bill: 20 km [N], 15 km [S] Chris: 3 km [N], 7 km [S 45 o E] Don: 3.5 km [S], 1 km [E], 2 km [S] Which friend has the greatest displacement from James’ house? Click A)Ann B)Bill C)Chris D)Don Ann:5.8 km Bill:5 km NOTE We need only consider the magnitude and not the direction. Chris:5.4 km Don:2.5 km Displacement Slide:

11. 20 km E < 20 km 0 Displacement is a vector from the starting point directly to the ending point. Click Displacement Slide:

12. 1 2 3 4 5 Click Displacement Slide:

13. Click Displacement Slide:

14. Starting point Ending point 2 km Click Displacement Slide:

15. The graph below represents the motion of an automobile as it moves northward. Determine the displacement of the automobile. NOTE Since velocity is plotted versus time, the area to the x-axis represents the distance traveled. Positive velocity (above the x-axis) means going forward. The area from the line to the x-axis represents forward distance since it has a positive value. Negative velocity (below the x-axis) means going backward. The area from the line to the x-axis represents backward distance since it has a negative value. Starting point Ending point Displacement The forward displacement is the area under the curve above the x-axis The backward displacement is the area above the curve below the x-axis Right represents North 160 m North ForwardBackward Forward Remember: displacement is the straight line from the starting point to the ending point. Note that for the problem, the time stops at the ending point (t = 20 s). However, according to the graph, the automobile continues to accelerate backwards. Note that for the problem, the time stops at the ending point (t = 20 s). However, according to the graph, the automobile continues to accelerate backwards. Click Displacement Slide:

16. … and good luck!