1. Height

2. Formulas Basic – a = ( v 2 − v 1 ) / t – v̄ = ( v 1 + v 2 ) / 2 – s = v̄ ∙ t Advanced – s = v 1 t + ½at² – v 2 2 − v 1 2 = 2as

3. How Long Does it Take an Object to Fall 80 meters? v 1 = 0 m/s s = − 80 m a = − 10 m/s² t = ?? s = v 1 t + ½at² s = 0 + ½at² 2s = at² 2s/a = t² = −160m/(−10m/s²) = 16 s² t = 4 seconds

4. Suppose we throw the object upward and it rises to a height of 80 meters. v 2 = 0 m/s s = 80 m a = − 10 m/s² t = ?? s = v 1 t + ½at² v 1 and t are both unknown Use v 2 2 − v 1 2 = 2as v 2 2 − 2as = v 1 2 0 − 2(−10m/s 2 ∙ 80 m) = v 1 2 1600 m 2 /s 2 = v 1 2 v 1 = 40 m/s a = (v 2 − v 1 ) / t t = (v 2 − v 1 ) / a = (0 − 40m/s )/−10m/s 2 = 4 seconds

5. A Trip Up and Down t = 0 sec v = +40 m/s t = 4 sec v = 0 m/s t = 8 sec v = −40 m/s v̄ = + 20 m/s v̄ = − 20 m/s

6. Up And Down When thrown in the air, objects take as long to go up as to come down. v 2 2 − v 1 2 = 2as Net displacement (up and down)  s = 0 v 2 2 − v 1 2 = 0  v 2 2 = v 1 2 v 1 = − v 2 v 1 is up, v 2 is down Neglecting Friction