1. Acceleration Section 1.3

2. Review What is the difference between vector and scalar quantities? Vector directions – x axis method How do we calculate velocity?

3. Objectives identify types of acceleration use formulas to analyze acceleration describe accelerated motion in position- time graphs and velocity-time graphs use slope to find acceleration in velocity- time graphs

4. Acceleration Change in velocity during specific time interval Vector quantity ◦ Magnitude and direction 2 types: ◦ Positive acceleration ◦ Negative acceleration

5. Positive acceleration Two ways:

6. Positive acceleration

7. Negative Acceleration Two ways:

8. Negative acceleration

9. Acceleration Formulas Acceleration = change in velocity time interval So the formula looks like…

10. Practice A racing car accelerates from rest to a speed of 200 km/h (55.6 m/s) [E] in 6.00 s. What is the acceleration of the car? ◦ Answer: 9.27 m/s 2 [E] A shuttle car accelerates from rest to a velocity of 50 m/s [upward] in 4.00 s. What is its acceleration? A baseball thrown at 25.0 m/s strikes a catcher’s mitt and slows down to rest in 0.500 s. What is the magnitude of the ball’s acceleration?

11. Position-Time Graphs What was the line of best fit like in all the position-time graphs that we have been creating? In accelerated motion, the line of best fit is a smooth curve

12. Practice Acceleration of a roller coaster (p. 149 #16) Example Problem b. Using the graph, identify the motion occurring in the time intervals below. Justify your answer. i. between t = 0.0 s and t = 3.0 s ii. between t = 3.0 s and t = 6.0 s iii. between t = 6.0 s and t = 8.0 s

13. Position-time graphs Two ways to show acceleration graphically: Positive accelerationNegative acceleration Slope is ___________ dd tt

14. Velocity-time graphs Change in velocity over time How do we calculate slope? Line of best fit will be straight, either increasing or decreasing Positive accelerationNegative acceleration v v tt

15. Practice Time t (sec) Velocity (m/s) [E] 0.0 1.02.0 4.0 3.06.0 4.06.0 5.06.0 4.0 7.02.0 8.00.0 Describe the motion

16. Rearranging the formula What is the formula for acceleration? Solve for: ◦ Time ◦ Final velocity

17. Practice Lightening McQueen is racing Doc around the dirt track by Radiator Springs. They both start at rest and accelerate at 26.0 m/s 2 in 5.00 sec. What velocity do they reach before the first corner? The Flash starts from rest and accelerates to 32.0 m/s 2 to chase after a villain. How long does it take him, if his final velocity is 27.0 m/s?