1. AIM: How do we define, calculate and graph acceleration? OBJ: Given notes and activity sheet SWBAT define, calculate and graph acceleration/deceleration with 70% accuracy DN: Review Speed Lab’s Graphing Motion Pt. 3 (Note: 80cm = 0.8m; speed: m/s); Hand-in Speed Lab and SLQ Quiz scantron. ACT: Introduction to Acceleration (notes) Text, read p. 22-27 HW: Complete Acceleration Activity Sheet; Work on Third Quarter Review Sheets. Study for Interim Exam (Tuesday, March 31)

2. SPEED FORMULA Instantaneous Speed = distance = d timet Average Speed = final distance – initial distance final time – initial time Average Speed = d f – d i where: i = starting t f – t i f = ending

3. How Can We Show Speed On A Graph? Time (s) Distance (m) 00 115 240 375 480 590 6 1)What was the average speed at 2 seconds? 2) What was the average speed at 3 seconds? 3) What was the average speed at 6 seconds? 4) What was the speed between 5 and 6 seconds? 5) During which interval was speed the highest?

4. ANSWER 1) 40m – 0m =40 = 20 m/s 2s – 0s 2 2) 75 – 0 = 75 = 25 m/s 3 – 0 3 3) 90 -0 = 90 = 15 m/s 6 – 0 6 4) 90-90 = 0 = 0 m/s 6-5 1 5)Between 2 and 3; steepest slope 75 – 40 = 35 = 35 m/s 3-21

5. Acceleration Acceleration: rate at which velocity changes (increasing speed, decreasing speed or changing direction)

7. Increasing Speed Acceleration: object’s speed increases Example: pitcher throws a ball Bat hits a ball Car passes another car Biking down hill

8. Decreasing Speed Deceleration: object’s slowing down; also called “negative acceleration” Example: catching a soft ball Car stops at a light Boat stops pulling water skier.

9. Changing Direction Acceleration: a constant speed with a change in direction. Example: car accelerates around a gentle curve in a road or changing lanes Runner accelerates around a curve on the track. Circular motion: ferris wheel’s accelerate

10. Calculating Acceleration Average Acceleration = Final speed-Initial speed (straight line)Time Units of Acceleration = m/s 2, km/h 2

11. Acceleration Example: FREE FALL

12. Graphing Acceleration To analyze the motion of an accelerating object, you can use: Speed vs. Time Graph 1.slanted, straight line = constant rate of acceleration 2. slope of the line = acceleration

13. Graphing Acceleration To analyze the motion of an accelerating object, you can use: Distance vs. Time Graph 1. curved line = acceleration upward curved line = increasing speed downward curved line = decreasing speed 2. slope of the line = speed