Review Slides 1 Displacement 2 Vectors Kinematics Graphs

Review Slides 1 Displacement 2 Vectors Kinematics Graphs Energy Power Springs Shadows Field of Vision Colors Concave mirrors Convex mirrors Refraction Lenses Optical Power 3 4 5 6 7 8 9 10 11 12 13 14 15 Slides Minutes 9 27 13 39 10 30 5 15 4 12 3 9 7 21 4 12 5 15 10 30 6 18

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

Distance versus Displacement Ending point Distance is a scalar. (It has no direction) Displacement is a vector. (It has direction) E NOT Starting point t en m ce pla Dis Ao Displacement is the straight line directly from the starting point to the ending point. Remember: Displacement has magnitude and direction. Click

Displacement Slide: An object travels the following distances: III II 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) B) C) D) I II IV 4 m [W] 2 m [S] 6 m [N] Displacement 9 m [E] Not drawn to scale Click

Displacement Slide: Riding her bike, Stefania traveled the following distance from point-A to point-D: AB = 4. 00 km North BC = 11. 3 km [S 45 E] CD = 8. 00 km West Determine Stefania’s displacement. A) 4. 00 km North B) 4. 00 km South C) 23. 3 km North D) 23. 3 km South E) 0 Note BD = CD = 8. 00 km and BA = AD = 4. 00 km Click

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

Displacement Slide: To go from his house to four of his friends, James must travel in different directions as listed below: NOTE Ann: 4. 8 km [N] , 3. 2 km [W] We need only consider Bill: 20 km [N] , 15 km [S] the magnitude and not Chris: 3 km [N] , 7 km [S 45 o E] the direction. Don: 3. 5 km [S] , 1 km [E] , 2 km [S] Which friend has the greatest displacement from James’ house? Ann: A) Ann 5. 8 km Bill: 5 km B) Bill Chris: 5. 4 km C) Chris Don: 2. 5 km D) Don Click

Displacement Slide: 0 m 20 k < <2 0 k m 20 km E Displacement is a vector from the starting point directly to the ending point. Click

Displacement Slide: 1 2 3 4 5 Click

Displacement Slide: Click

2 km Ending point Displacement Slide: Starting point

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

… and good luck!