1. Physics 9-26 Constant acceleration Problems

2. Homework 10 examples of constant acceleration with which you come into contact Any interesting examples?

3. Finish Motion Detector Graphs Creation All those that need a graph, will walk today Questions on what is being asked of you to complete graph task?

4. Test Grades Available As People are walking, take a look at the score Answers and tests will be available to you tomorrow

5. Using Constant (Uniform) Acceleration Equations What is the identifier?

6. The Con A equations V f = V i + at(d) d = V i t + ½at 2 (V f ) d = ½ (V f + V i ) t(a) V f 2 = V i 2 + 2ad(t)

7. The 5 th Con A equation D = v f t - ½at 2 (v i ) Not used much because the initial velocity is generally known and zero.

8. Steps to solve Con A problems Identify givens, what is wanted, equation identifier Check units, convert if needed Solve equation for unknown Check to see if answer has units, makes sense

9. #1 Starting from rest, a race car moves 110 m in the first 5.0 s of uniform acceleration. What is the car’s acceleration?

10. #1 answer Have initial v, d, and t Need a Identifier is final v use d = V i t + ½at 2 Answer is 8.8 m/s 2

11. #2 A bike rider accelerates constantly to a velocity of 7.5 m/s during 4.5 s. The bike’s displacement is +19m. What was the initial velocity of the bike?

12. #2 answer Have final v, t, and d Need initial v Identifier is a Use V f = V i + at Answer is 0.9 m/s

13. #3 A car is initially sliding backwards down a hill at -25 km/h. The driver guns the car. By the time the cars velocity is +35 km/h, it is 3.2 m from its starting point. Assuming the car was uniformly accelerated, find the acceleration.

14. #3 answer Have initial and final velocities, d Want a Identifier is t Use V f 2 = V i 2 + 2ad Convert km/h to m/s by dividing # by 3.6 7.3 m/s 2

15. Problem #4 A man drops off the top of the empire state building (assume no air resistance). Acceleration due to gravity is -9.8 m/s 2 and the height of the building is 410 m How long does the fall take? How fast is he going just before impact?

16. For any object in freefall Acceleration is always - 9.8 m/s 2. Can be used as a hidden value Displacement will have a negative value because it is going down

17. #4 answers Have initial velocity, a, and d Want final velocity Identifier is t Use V f 2 = V i 2 + 2ad Answers are

18. Homework Complete motion detector graphs Con A handout of problems