1. Constant, Average and Instantaneous Velocity Physics 11

2. Constant Velocity  If an object is traveling at a constant velocity, a position time graph will result in a straight line (constant function)  This is referred to as uniform or non-accelerated motion

3. Average Velocity  It is rare that an object will travel at the same velocity throughout its trip so it is often useful to consider the average velocity  The average velocity is taken between two points and is determined as the slope of a line connecting those two points

4. Average Velocity  Plot the following position time data for a car accelerating from rest to 90.km/h. Determine the average velocity for the following time intervals: 0s to 10s 0s to 3 s 3s to 6s 6s to 9s 4s to 5s Time (s)Position (m) 00 11.25 25 311.25 420 531.25 645 761.25 880 9101.25 10125

5. Instantaneous Velocity  The instantaneous velocity is the velocity at one specific instant in time  This is determined by drawing a tangent line to that point on the graph and determining the slope of the tangent line

6. Instantaneous Velocity Calculate the slope of the tangent line to find instantaneous velocity!

7. Practice Problems  Page 42 #7, 8  Using Figure 2-26 on page 42, calculate the instantaneous velocity of the object at t = 30 s.