1. l http://vimeo.com/609333 http://vimeo.com/609333EXAMPLE: l Kingda Ka Coaster: 0 – 128 mph in 3.5 seconds through hydraulic system & compressed air. Jennifer Brown Section 4.3

2. l Acceleration – The rate at which your speed (or velocity) changes. If your speed increases by 1 meter per second for each second, then your acceleration is 1 meter per second per second (m/s 2 ). Sections 4.1 - 4.3 Jennifer Brown

3. Sections 4.1 - 4.3

4. l Can you have acceleration if you are travelling at constant speed? No: There is zero acceleration at constant speed because the speed does not change. Jennifer Brown Sections 4.1 - 4.3

5. l Speed and acceleration are not the same thing. l You can be moving (constant speed), but have no acceleration (think cruise control). Jennifer Brown Sections 4.1 - 4.3

6. l Acceleration describes how quickly speed changes. change in speed change in time l Acceleration is the change in speed divided by the change in time. Jennifer Brown Sections 4.1 - 4.3

7. Jennifer Brown Sections 4.1 - 4.3

8. l An acceleration of 20 km/h/s means that the speed increases by 20 km/h each second. l The units for time in acceleration are often expressed as “seconds squared” and written as s 2. Jennifer Brown Sections 4.1 - 4.3

9. l The word “acceleration” is used for any change in speed, up or down. l Acceleration can be positive or negative, which makes it a what? VECTOR!VECTOR! Jennifer Brown Sections 4.1 - 4.3

10. l Positive acceleration adds more speed each second. l Things get faster. l Speed increases over time. Jennifer Brown Sections 4.1 - 4.3

11. l Negative acceleration subtracts some speed each second. l Things get slower. l People sometimes use the word deceleration to describe slowing down. Jennifer Brown Sections 4.1 - 4.3

12. l How do we solve problems dealing with acceleration? : 1) Calculate the acceleration of an airplane that starts at rest and reaches a speed of 45 m/s in 9 seconds? Answer: 5 m/s 2 2) Calculate the acceleration of a car that slows from 50 m/s to 30 m/s in 10 seconds? Answer: -2 m/s 2 Jennifer Brown Sections 4.1 - 4.3