1. Kinematics Equations Just what you have been waiting for…more math!

2. Kinematics What are the four ways we can describe motion? 1. With words 2. With graphs 3. With diagrams 4. With equations

3. Equations  Remember that the basis for all equations is some sort of graphed experimental data  The concept of slope = (rise/run) gives us the equations

4. Variables  d = distance Measured in meters (m)  v = velocity Measured in meters/second (m/s)  a = acceleration Measured in (meters/second)/second (m/s 2 )  t = time Measured in seconds (s)

5. Kinematics Equations v = (  d/  t) a = (  v/  t) v f = v o + at d = d o + ½(v o + v)t d = d o + v o t + ½ at 2 v f 2 = v o 2 + 2ad

6. Problem Solving Tips 1. Draw a picture of what is happening 2. Underline important information in the problem 3. Make a list of known variables 4. Make sure variables are in the correct units 5. Choose equation(s) that fits known variables 6. Solve equations 7. Double check answer – does it make sense?

7. Example #1 A car accelerates uniformly from rest to a speed of 17.8 m/s in 12 s. What is the distance the car travels in this time? What is the acceleration of the car?

8. Example #1 (continued) Given: v 0 = 0 m/s v f = 17.8 m/s t = 12 s Trying to find: d = ? a = ? Equation: d = d o + ½(v o + v)t Equation: v f 2 = v o 2 + 2ad Solve: d = 0 + ½(0 +17.8)(12) d = 106.8 m Solve: (17.8) 2 = 0 2 + 2(a)(106.8) a = 1.48 m/s 2

9. Example #2  A jet flying at 522 km/hr is accelerated at the rate of 23.1 m/s 2 for 20.0 s. What is its final velocity? What distance does the plane cover during this time?

10. Example #2 (continued) Given: v 0 = 522 km/hr t =20.0 s a = 23.1 m/s 2 Trying to find: v f = ? d = ? Equation: v f = v o + at Equation: v f 2 = v o 2 + 2ad Solve: v f = (145 ) + (23.1)(20.0) v f =607 m/s Solve: (607) 2 = (145) 2 + 2(23.1)(d) d = 7520 m

11. Homework  In your lab notebook: Lunchroom Walk Lab Inclined Plane Lab  Homework so far: Metric Conversion WS

12. More Homework!  Chapter 5  #15, 16, 20, 28, 35, 44, 46, 49, 55, 59, 62  Remember to follow the problem solving steps I showed you previously  Show all work and label all answers!