Accelerated Motion Chapter 3

Acceleration Section 3-1

Changing Velocity Uniform motion is smooth and unchanging, non-uniform motion causes the feeling of a push or pull Motion diagrams for objects with changing velocity will not be constant Example: page 58

Velocity-Time Graph Velocity-Time Graph – graphs velocity vs. time Velocity on the Y-axis Time on the X-axis Acceleration – the rate at which an objects velocity changes

Acceleration Average Acceleration – the change in velocity divided by the time interval Instantaneous Acceleration – the change in velocity at an instant in time Can be found by drawing a tangent line on a velocity-time graph

Acceleration on a Motion Diagram The difference in velocity vectors in a motion diagram will show you the acceleration Example: page 60

Positive and Negative Acceleration Positive acceleration – an increase in speed in the positive direction, or a decrease in speed in the negative direction Negative Acceleration – a decrease in speed in the positive direction, an increase in speed in the negative direction Page 61 Figure 3-7

Determining Acceleration from a Velocity-Time Graph Page 62 Figure 3-8 Line A – Positive Velocity, 0 Acceleration Line B – Positive Velocity, Positive Acceleration Line C – Positive Velocity, Negative Acceleration Line D – Negative to Positive Velocity, Positive Acceleration Line E – Negative Velocity, 0 Accleration

Calculating Acceleration The acceleration of an object can be found by the slope of a velocity-time graph Average Acceleration – equal to the change in velocity, divided by the time it takes to make that change Example Problem 2