8 2 part 1 Average Velocity Slope of

8. 2 part 1 - Average Velocity & Slope of Position-Time Graph • Speed ( ) is the distance an object travels divided by the time interval of travel. w Speed is a scalar quantity. • Velocity ( ) is the displacement of an object divided by the time interval. w Velocity is a vector quantity therefore must include direction. w Velocity describes how fast an object’s position is changing. w The direction of the velocity is the same as the direction of the displacement. • The SI unit for speed and velocity is metres per second (m/s). These two ski gondolas have the same speed but have different velocities since they are travelling in opposite directions.

Calculating the Slope of the Position-Time Graph • Recall from math class: The slope of a graph is represented by rise/run. • On a position-time graph the rise is the change in position or displacement, and the run is the change in time (or the time interval), ( ) • Therefore the SLOPE of a position of by: S vs. time graph is calculated T I N U slope: • The steeper the slope, the greater Which jogger’s motion has a greater slope? Which jogger is moving faster?

Do you remember how to find the SLOPE OF A LINE? Do the mini-assignment on your notes sheet

Average Velocity • The slope of a position-time graph is the object’s average velocity. • Average velocity is the rate of change in position for a time interval. • The symbol of average velocity is: On a position-time graph: • A positive slope means that the object’s average velocity is forward. • A negative slope means that the object’s average velocity

PUTTING IT ALL TOGETHER Do the mini-assignment on your notes sheet

Assignment 1. Workbook p. 157, 159, 160 2. Text p. 366 #1 -5