1. Science Starter! 1.Submit “Dollar Bill” activity on teacher desk. 2.Review homework answers with a partner/small group: Page 82, #’s 97-99

2. Think about it… Consider a ball thrown directly overhead. 1.Describe what happens to its velocity (in terms of speed and direction) on (a) the way up, and (b) the way down. 2.Describe what happens to its acceleration on (c) the way up, and (d) the way down.

4. Vertical Motion 1.Objects thrown downward - Initial velocity is NOT zero - Initial velocity is NEGATIVE (“down”) 2. Objects thrown upward - Initial velocity is NOT zero - Initial velocity is POSITIVE (“up”)

5. Example 1 A book is thrown downward at 5 m/s from a window on the third floor of a high school, which is 10.0 m above the ground. (a)What is the velocity of the book just before it hits the ground? (b)How much time does the book spend in the air before it hits the ground? (c)If the book was thrown UPWARD at 5 m/s instead, how fast would it be traveling just before it hits the ground?

6. v o = -5 m/s a g = - 9.8 m/s 2 y o = 10 m y = 0 m (a)v = ? (b)t = ? (c)v o = 5 m/s ; v = ? (a) v 2 = v o 2 + 2a(y – y o ) v 2 = (- 5) 2 + 2(- 9.8)(0 – 10) v 2 = 25+ 196 = 221 v = - 14.9 m/s (b) v = v o + at (- 14.9) = (- 5) + (- 9.8)(t) (- 9.9) = (- 9.8)(t) t = 1.01 s

7. v o = + 5 m/s a g = - 9.8 m/s 2 y o = 10 m y = 0 m (c) v 2 = v o 2 + 2a(y – y o ) v 2 = (+ 5) 2 + 2(- 9.8)(0 – 10) v 2 = 25+ 196 = 221 v = - 14.9 m/s

8. t (s)a (m/s 2 )v (m/s)y (m) 0 - 9.829.478.4 1- 9.819.6102.9 2- 9.89.8117.6 3- 9.80122.5 4- 9.8 117.6 5- 9.8-19.6102.9 6- 9.8-29.478.4 7- 9.8-39.244.1 8-9.8-490

10. t (s)a (m/s 2 )v (m/s)y (m) 0 - 9.829.478.4 1- 9.819.6102.9 2- 9.89.8117.6 3- 9.80122.5 4- 9.8 117.6 5- 9.8-19.6102.9 6- 9.8-29.478.4 7- 9.8-39.244.1 8-9.8-490

11. Key Ideas for Vertical Motion On way up: v is (+) a g = - 9.8 m/s 2 Speed decreases At highest point: v = 0 a g = - 9.8 m/s 2 On way down: v is (-) a g = - 9.8 m/s 2 Speed increases If object returns to height from which it was thrown: (y = y 0 ) then: v = (- v 0 )