Physical Science: Chapter 11 Acceleration

Physical Science: Chapter 11 Acceleration When the velocity of an object changes the object is accelerating.

Physical Science: Chapter 11 Acceleration Remember that velocity includes speed AND direction

Physical Science: Chapter 11 Acceleration So if the speed of an object increases (speeds up) it is accelerating

Physical Science: Chapter 11 Acceleration AND if the speed of an object decreases (slows down) it is ALSO “accelerating”

Physical Science: Chapter 11 Acceleration AND if the motion of an object changes direction it is ALSO “accelerating”

Physical Science: Chapter 11 Acceleration Acceleration by changing direction

Physical Science: Chapter 11 Acceleration Acceleration = final velocity – initial velocity time (accelerating) a = vf –vi = m/s = m/s2 Δt s

Physical Science: Chapter 11 Acceleration Δt = v f – vi a Δv = (a) x (Δt)

Physical Science: Chapter 11 Acceleration Do Practice Problems p. 375 (1, 2, 3, 4)

Physical Science: Chapter 11 Acceleration Do Practice Problems p. 377 (1, 2, 3, 4) 1). a = vf –vi = 4.0m/s-0.0m/s = 1.6m/s2 Δt 2.5s on path 2). a = vf –vi =0.8m/s-0.5m/s= 0.075m/s2 Δt 4.0s toward shore

Physical Science: Chapter 11 Acceleration Do Practice Problems p. 377 (1, 2, 3, 4) 3). a = vf –vi = 9.6m/s-12m/s = -3.0m/s2 Δt 0.8s north (note: you could say 3.0 m/s2 south) 4). Δt = vf –vi = 26.8m/s-24.6m/s = 0.85s a 2.6 m/s2

Physical Science: Chapter 11 Acceleration On a distance-time graph an object with increasing acceleration has a line curving up.

Physical Science: Chapter 11 Acceleration On a distance-time graph an object with negative acceleration has a line going up, but curving down.

Physical Science: Chapter 11 Acceleration On a velocity-time graph, plot Velocity on the y axis time on the x axis

Physical Science: Chapter 11 Acceleration On a velocity-time graph, a constant upward sloping line shows constant positive acceleration

Physical Science: Chapter 11 Acceleration On a velocity-time graph, a line curving upward shows INCREASING positive acceleration

Physical Science: Chapter 11 Acceleration On a velocity-time graph, a line with DECREASING slope shows positive acceleration

Physical Science: Chapter 11 Acceleration On a velocity-time graph, a “flat” line (no slope) shows NO acceleration (constant velocity)

Physical Science: Chapter 11 Acceleration On a velocity-time graph, a constant downward sloping line shows negative constant acceleration

Physical Science: Chapter 11 Acceleration On a velocity-time graph, lines below 0 (zero) show movement “backwards” (towards the starting point)

Physical Science: Chapter 11 Acceleration Velocity-time graph summary:

Physical Science: Chapter 11 Acceleration Mini-Quiz #4 1). What is graphed on the y-axis on a velocity-time graph? 2). What is graphed on the y-axis of a distance-time graph? 3). What does a constant upward sloping line on a distance-time graph show?

Physical Science: Chapter 11 Acceleration Mini-Quiz #4 In this graph what is happening: 4). between A & B? 5). Between B & C 6). Between C & D

Physical Science: Chapter 11 Acceleration Mini-Quiz #4 In this graph what is happening: 7). In part A? 8). In part B? 9). In part C?

Physical Science: Chapter 11 Acceleration Mini-Quiz #3 (Answers) 1). What is graphed on the y-axis on a velocity-time graph? VELOCITY 2). What is graphed on the y-axis of a distance-time graph? DISTANCE 3). What does a constant upward sloping line on a distance- time graph show? CONSTANT POSITIVE ACCELERATION

Physical Science: Chapter 11 Acceleration Mini-Quiz #3 In this graph what is happening: 4). between A & B? Constant positive acceleration 5). Between B & C velocity (speed) 6). Between C & D Constant negative acceleration

Physical Science: Chapter 11 Acceleration Mini-Quiz #3 In this graph what is happening: 7). In part A? Constant positive velocity 8). In part B? Constant negative acceleration 9). In part C? Constant neg. acceleration, “BACKWARDS”.