1. Velocity and Acceleration I’m the king of the world!!!! Woo-hoo!!!

2. Velocity Speed only describes how fast something is moving Speed only describes how fast something is moving Velocity describes both speed AND direction! Velocity describes both speed AND direction!

3. Velocity Concep question: Concep question: Picture two sports cars racing down the highway. The Ferrari is traveling west while the Lamborghini is traveling east. They both have a speed of 100km/h. What can you conclude about their velocities? a.Ferrari’s v is greater b. Lamborghini’s v is greater c. Their velocities are the same c. Their velocities are the same d. Their velocities are different d. Their velocities are different

4. Velocity The answer is d. Both cars have the same speed, however the direction in which they are traveling is different. Their velocities are different because their directions are different. The answer is d. Both cars have the same speed, however the direction in which they are traveling is different. Their velocities are different because their directions are different.

5. Change in velocity Speed may not always be constant. Speed may not always be constant. The velocity of an object may change, even if the speed remains the same. The velocity of an object may change, even if the speed remains the same.

6. Acceleration Acceleration is the rate of change of velocity Acceleration is the rate of change of velocity Velocity includes both speed and direction, therefore acceleration is both the rate of change in velocity and direction of that change. Velocity includes both speed and direction, therefore acceleration is both the rate of change in velocity and direction of that change.

7. Acceleration If acceleration is in the same direction as the object, the objects speeds up. If acceleration is in the same direction as the object, the objects speeds up. If acceleration is the opposite direction as the object, the object slows down. If acceleration is the opposite direction as the object, the object slows down.

8. Acceleration Acceleration also depends on the time interval. Acceleration also depends on the time interval. To calculate the acceleration of an object, divide the change in velocity by the time. To calculate the acceleration of an object, divide the change in velocity by the time. a=v f -v i or Δv a=v f -v i or Δv t t t t

9. Acceleration Units The unit for velocity is meters / second m/s The unit for velocity is meters / second m/s The unit for time is seconds (s) The unit for time is seconds (s) Therefore, the unit for acceleration is meters/seconds = m/s 2 Therefore, the unit for acceleration is meters/seconds = m/s 2 seconds seconds “Meters per second squared”

10. Acceleration Sample Problem A race car sits at the starting line at Atco raceway. The light turns green and the driver presses the pedal to the metal. The velocity changes from 0 m/s to 60m/s in 6 seconds. What is the acceleration of the car? A race car sits at the starting line at Atco raceway. The light turns green and the driver presses the pedal to the metal. The velocity changes from 0 m/s to 60m/s in 6 seconds. What is the acceleration of the car?

11. Solution: List the known information: List the known information: initial velocity (v i ): 0 m/s Final velocity (v f ): 60 m/s Time: 6 seconds A= 60m/s – 0 m/s = 10 m/s 2 6 s 6 s

12. Homework: Questions 1-3 on page 67. Questions 1-3 on page 67. Complete mini-lab… Complete mini-lab… Does greater velocity require greater acceleration?