Speed

1. Speed • Speed is distance traveled in a certain period of time.

2. Velocity • The distance an object travels in a certain period of time in a specific direction.

3. Speed vs. Velocity • Velocity • A measurement of both the speed and direction of an object’s movement • relative to a reference point • May be + or – • Speed • How fast an object moves

4. Velocity: GUESS & Triangle d V= d/t v t t = d/v d = vt

5. Constant Velocity Lab • Question/Purpose: Use a constant velocity vehicle to generate distance-time data and find the equation for velocity. • Hypothesis: How fast in m/s do you think a toy car travels?

6. Setup and Procedures • Starting at 0, use the tape to mark off 20 cm increments for a total distance of 2 meters. • Start your car behind zero. When the car reaches the 0 mark, start the stopwatch. • Stop the stopwatch as the car reaches the 20 cm mark. • Record the times in the data table. • Repeat steps 2 & 3 for 40 cm, 60 cm, 80 cm, etc…

7. Data Table

8. Analysis-Graph Your Data! • Draw an x and y axis • Put TIME on the x-axis • DISTANCE on the y-axis • Scale each axis using even increments • Label each axis with its name and unit • Plot your data points • Draw a line of best fit

9. Conclusions • Using your data, calculate the slope of the line. Include units with your calculations. (y2 – y1/x2 – x1) • What is the unit for the slope of your line? Given these units, what does the slope represent? • What would be the correct equation to find the velocity of an object?

10. Bell Ringer: What are the first three things that come to mind when you hear the term “motion”? Essential Question: When an object changes position with respect to a frame of reference, the object is ___ __________. Tuesday, August 26, 2014 Agenda: Motion Pretest Velocity Lab Class Velocity Problems in motion

11. Motion Circle Map Motion Song!! La -lalaaa Motion

12. Motion Circle Map Motion Song!! La -lalaaa Motion

13. Motion Circle Map Motion Song!! La -lalaaa Motion

14. Bell Ringer: What is the difference between speed and velocity? Essential Question: What equation is used to calculate velocity? Wednesday, August 27, 2014 Turn in Homework: Vocabulary Velocity Lab Report Agenda: Motion Circle Map Solve for V practice problems (turn in) Both describe how fast motion is happening. Velocity gives a direction (+/-) as well. V = d/t

15. Bell Ringer: Based on your conclusions from yesterday’s lab, determine a commonly used unit for velocity. EQ: Fill in the following triangle d Thursday, August 29, 2014 Agenda: Motion Song Solve for d or t practice problems Velocity is commonly measured in m/s v t

16. Bell Ringer: How would you rearrange the velocity equation to solve for distance. Thursday, August 29, 2013 Agenda: Distance & Displacement Solve for d or t practice problems Quiz Tomorrow! d = v t

17. Bell Ringer: How would you rearrange the velocity equation to solve for time. Essential Question: Make a prediction-what is the speed of a cheetah? Friday, August 29, 2014 Agenda: Review Velocity Quiz Graphing d vs t speed relay videos t = d/v

18. ReviewSpeed vs. Velocity • Velocity • A measurement of both the speed and direction of an object’s movement • relative to a reference point • May be + or – • Speed • How fast an object moves

19. Review Analysis-Graph Your Data! • Draw an x and y axis • Put TIME on the x-axis • DISTANCE on the y-axis • Scale each axis using even increments • Label each axis with its name and unit • Plot your data points • Draw a line of best fit

20. Review How fast is a high school sprinter traveling if he covers 100 m in 10.9 seconds? G U E S S

21. Review How long would it take a punter to kick a football 47 m if the ball travels at 11.3 m/s. G U E S S Convert this value into minutes.

22. Tuesday September 2, 2014 BR: Describe acceleration in your own words. Give an example. • A change in velocity over a change in time

23. Acceleration

24. Acceleration • A change in velocity over a change in time • Includes: • speeding up, • slowing down, • and changing directions.

25. Equation acceleration = final velocity – initial velocity time OR a = vf – vi t vf-vi a t

26. Units for Acceleration • Combine the units for velocity and time: a = v = m/s or m/s2 t s

27. Sample Problem #1 An Indy-500 car’s velocity increases from 4.0 m/s to 36 m/s over a 4.0 second time period. What is its average acceleration? Use the GUESS method!

28. SolutionG U E S S

29. Sample Problem #2 The same race car slows from 36 m/s to 15 m/s over 3.0 seconds. What is its average acceleration?

30. SolutionG U E S S The negative sign means the car is slowing down.

31. Sample Problem #3 A supersonic jet sitting on the runway accelerates at a rate of 23.1 m/s2 to reach a final speed of 607 m/s. How much time does it take for the jet to accelerate?

32. SolutionG U E S S

33. Tuesday September 2, 2014 BR: Describe acceleration in your own words. Give an example. • A change in velocity over a change in time: speeding up, slowing down, and changing directions EQ: What is the equation for acceleration? • a = (vf – vi ) t

34. Bell Ringer G U E S S a = 3.0 m/s2 vi = 6.0 m/s t = 5.0 s Vf vf - vi = at vf = 21 m/s vf – 6 m/s= (3.0 m/s2)(5.0 s) vf – 6 m/s= 15 m/s vf = 15 m/s + 6 m/s

35. Wednesday, September 3, 2014 BR: A car travels at a constant velocity of 6.0 m/s and then speeds up with a steady acceleration of 3.0 m/s2. Calculate the car’s speed after accelerating for 5.0 s. 21 m/s2 EQ: Rearrange the acceleration equation to solve for Vi or Vf. Vi –Vf = at

36. Thursday, September 4, 2014 BR: When is acceleration negative? Acceleration is negative when an object is slowing down; velocity decreases. EQ: Describe a similarity between acceleration and velocity. • Include direction (+/-) • Describe an object’s motion • Complete Acceleration Lab Analysis • Acceleration Practice Problems • Quiz Tomorrow

37. Friday, September 5, 2014 BR: Rearrange the acceleration to solve for final velocity (Vf-vi) = at EQ: A car traveling at 5.5 m/s speeds up with a steady acceleration of 3.5 m/s2. Calculate the car’s speed after accelerating for 7.0 s. • Review • Acceleration Quiz • a = (Vf-vi) • t

38. Bell Ringer G U E S S

39. Review • Define acceleration • Units for acceleration • When is acceleration ? When is acceleration ? • Equation for acceleration: m/s2 a = (vf-vi) t

40. Friday, September 5, 2014 BR: Rearrange the acceleration to solve for final velocity (Vf-vi) = at EQ: A car traveling at 5.5 m/s speeds up with a steady acceleration of 3.5 m/s2. Calculate the car’s speed after accelerating for 7.0 s. 30 m/s • Review • Acceleration Quiz • a = (Vf-vi) • t • Turn in yesterday’s practice problems

41. What does the slope of a distance-time graph tell you about an object? It tells you the VELOCITY of the object.

42. Calculate Velocity

43. Slope Review What is the relationship between distance and time according to this graph? Time and distance are directly proportional. As more time passes, the distance traveled increases.

44. Who is traveling at the greatest velocity?

45. Interpreting Position-Time Graphs • Who has the greater velocity? • Who starts ahead of the starting line? • What happens at 2 seconds? Anna Bob Anna passes Bob

46. Describe what is happening in this graph.

47. Describe what is happening in this graph.

48. Draw a d vs. t graph to represent the following scenario: Bill left home and jogged for 3 km. He rested for a moment then sprinted for 3 more km. He finally turned around and jogged 6 km back home.

49. What does the slope of a velocity-time graph tell you about an object? It tells you the acceleration of the object.

50. Rudy left home in a hurry. He picked up speed as he drove down Watson Road, but he saw a police car and slowed down to a steady pace. V vs t Slope= • D vs t Slope =