1. Acceleration: a change in Velocity!

2. An object traveling at the same rate in the same direction, is in uniform motion. NON uniform motion - there must be an increase or decrease in Velocity. Acceleration is a vector quantity. It is the rate at which velocity CHANGES with time. a

3. Any speeding up, slowing down, or change in the direction of motion means that velocity is changing. Any of this is acceleration. a = v t v = 6 m/s [S] v = 6 m/s [W]

4. = ∆t∆t ∆v∆v a = v final - v initial t final - t initial

5. If a cheetah reaches a speed of 19 m/s in 2.0 s from a standing start, what is the cheetah's acceleration? = + 9.5 m/s 2 v 1 = 0 m/s = ∆t ∆v v final - v initial t final - t initial v 2 = +19 m/s a = 2 +19 - 0 a

6. Find the acceleration of a bike as it from +13.9 m/s to +8.3 m/s in 3.5 s. = - 1.6 m/s 2 v 1 = +13.9 m/s = ∆t ∆v v final - v initial t final - t initial v 2 = +8.3 m/s a = 3.5 +8.3 – (+13.9) a slows down

7. A speed skater at the start line accelerates at +4.1 m/s 2, and reaches a top speed in 3.2 seconds. What is the change in velocity? ∆v = ? = ∆t ∆v ∆t = 3.2 s a a = + 4.1 m/s 2 = 3.2 ∆v 4.1 (3.2) = ∆v4.1 (3.2) + 13 m/s

8. a = v t d = d 2 - d 1 v = d t t = t 2 - t 1

9. P-T Graph