Ch. 11: Motion

1. Ch. 11: Motion

2. Motion • Problem: • Is your desk moving? • We need a reference point... • nonmoving point from which motion is measured

3. Motion A change in position Frame of reference = system of objects that are not moving with respect to one another

4. Distance versus Displacement Distance is the length of a path between two points SI Unit is meter (m) Displacement is the length from the starting point to the ending point

5. Speed Distance Velocity time the ratio of the distance (d) an object moves to the amount of time (t) the object moves SI Unit is meter per second (m/s) V=d/t V = velocity!

6. Speed Average speed = computed for the entire duration of the trip Instantaneous speed = measured at a particular instant Velocity (V) = the speed and direction an object is moving Vector = a quantity that has magnitude and direction

7. d t v Calculations • Your neighbor skates at a speed of 4 m/s. You can skate 100 m in 20 s. Who skates faster? WORK: v = d ÷ t v = (100 m) ÷ (20 s) v = 5 m/s You skate faster! GIVEN: d = 100 m t = 20 s v = ?

8. d t v Calculations • Sound travels 330 m/s. If a lightning bolt strikes the ground 1 km away from you, how long will it take for you to hear it? GIVEN: v = 330 m/s d = 1km = 1000m t = ? WORK: t = d ÷ v t = (1000 m) ÷ (330 m/s) t = 3.03 s

9. Graphing speed • Slope tells me SPEED! • Horizontal part tells me the object stop moving

10. Graphing speed Curved parts tells me object is increasing and decreasing speed Straight portions tell me constant speed Greater the slope the higher the speed, vice versa

11. Distance-Time Graphs

12. Distance-Time Graphs No motion=stopped

13. V=d/t Florence Griffith Joyner set a world record by running 200m in 21.34s. What was her average speed?

14. Acceleration Is the rate at which velocity changes changes in speed changes in direction changes in speed and direction SI unit is meter per second per second (m/s2)

15. Acceleration • The triangle is the Greek symbol delta, it means “change in” • Vf = final velocity • Vi = initial velocity • Vf-Vi (final minus initial)

16. Graphing acceleration

17. Graphing Acceleration Slope of Speed-Time graph tells me acceleration! Horizontal part tells me object is at constant speed Slope downward tells me object is slowing down (decelerating)

18. Speed-Time Graph

19. Speed-Time Graph Constant speed/velocity STOPPED!

20. a=Vf-Vi/t The speed limit changes from 55m/s to 0m/s. To make the change in 10s, what acceleration will it require?

21. a=Vf-Vi/t A car’s acceleration is 3m/s2. if the car started at rest and it only took 10s for the car to reach this acceleration, what is the car’s final velocity?

22. IAN pg. 27: Acceleration Title: Acceleration Define acceleration from notes. Write acceleration equation and define all varaibles (i.e. “a” stands for acceleration) Write all units (i.e. acceleration is measured in m/s2) Complete the sample problems on handout and glue into notebook.

23. IAN pg. 28: Speed-Time Graphs Title: Speed-Time Graphs Glue in the 4 graphs we labeled together Write the following information: Slope = __________________ A synonym for slowing down is _____ Label on the Negative Acceleration Graph where the object is moving at CONSTANT ACCELERATION

24. Agenda: 4/17 Trade cell phone for calculator! Be in your new seat with your PhysiFacts notebook and be ready to start when the bell rings! Today’s Order of Operations: 2nd block: review #1 on PF from yesterday! PhysiFacts = Acceleration Problems 11-19 (plus resubmit Velocity questions) Velocity and Acceleration Word Problems Ch. 11 Assessment (quiz grade)

25. PhysiFacts 4.5 Delilah can run 50 meters in 10 seconds. What is her velocity? d = 50 m, t=10 s V = d/t ; v = 50/10 = 5m/s

26. Chapter 11 Assessment – p. 350-351 Will count as a quiz grade! 1-10 – just write the letter answer Draw the concept map and fill it in Make sure to turn in 1-15 to the basket!

27. IAN pg. 24: Distance vs. Displacement • Define both terms – DISTANCE and DISPLACEMENT. • ON HANDOUT: • Trace the DISTANCE in purple • Trace the DISPLACEMENT in orange • Trim handout and glue/tape on page under definitions

28. PhysiFacts 4.5 Delilah can run 50 meters in 10 seconds. What is her velocity? Zoey has a top speed of 7m/s. It takes her 20 seconds to run from the house to the field. How far away is the field? Roxy can walk at a pace of 0.3m/s. The wind blew her favorite toy 300 meters away. How long will it take her to retrieve her toy?

29. IAN pg. 25: Speed/Velocity • Define velocity. • Write the velocity equation and circle. • Define the variables (i.e. v stands for velocity) • Write the units for each variable • (i.e. velocity is measured in m/s) • Complete the practice problems on the handout and glue the handout on the page.

30. IAN pg. 26: Distance-Time Graphs Title: Distance-Time Graphs Glue in the 4 graphs that we labeled together Label the portion of Varying Speed graph that represents no motion (stopped) Write the following information: Slope = ______________ X – axis = ______________ Y – axis = ______________

31. IAN pg. 26: Distance-Time Graphs Title: Distance-Time Graphs Glue in the 4 graphs that we labeled together Label the portion of Varying Speed graph that represents no motion (stopped) Write the following information: Slope = ______________ X – axis = ______________ Y – axis = ______________