1. Motion
10-1 Notes

2. matter- anything that has mass and volume
matter- anything that has mass and volume. mass- a measure of how much matter an object is made of. Position describes the location of an object.

3. Frames of Reference Object or point from which motion is determined
Can be straight-line
distance
Can be a total distance
Motion is a change
in position relative to
a frame of reference

4. - A position is compared to a reference point.
- Describing a position
- A position is compared to a reference point.
-Position can be described using distance and direction.

5. What is motion?
If you are standing in one place, and your friend walks by you, are you moving relative to your friend?
Is your friend moving relative to you?
Is either of you moving relative to the earth?

6. Answer:
You are moving relative to your friend, and your friend is moving relative to you!
You are not moving relative to the earth, but your friend is. You are both moving relative to the sun!

7. What is motion?
If you and your friend are walking down the hall together at the same speed, in the same direction, are you moving relative to your friend?
Is your friend moving relative
to you?
Are either of you moving
relative to the Earth?

8. Answer:
You are NOT moving relative to your friend, and your friend is NOT moving relative to you. You both are moving relative to the earth.

9. Matter is in motion if it is changing position
Matter is in motion if it is changing position. Matter is at rest if the object does not change position. Distance is the amount of space between two points.

11. 10-2 Notes Speed and Velocity

12. speed- is defined as the change in position divided by time, or a measure of how fast something is moving. Speed (S)= distance (d) time (t) Common Units for Speed: m/s, cm/s, ft/s, mph, km/h velocity- speed in a specific direction EX. 60 mph NW

13. Relationships between speed, distance and time.
speed = distance / time or s = d/t
distance = speed x time (st)
time = distance/speed or d/s
speed is referred to as v in some equations and not s.
Solving physics problems
Step 1 – What are you Looking For? (LF)
Step 2 – What has been Given to you? (G)
Step 3 – Identify any relationships/formulas (R/F)
Step 4 – Solve the problem (S)

14. Velocity Speed in a given direction.
What is the velocity of a boat that travels south from St. Peter to Mankato (10 miles) in 15 minutes?

15. Answer Speed = distance ÷ time Speed = 10 miles ÷ 15 minutes
Speed = 0.67 mi/min
Velocity = 0.67 mi/min South

16. Speed Speed = Distance ÷ Time D_ S T
Example: A car travels 300km in 6 hours. What is the speed of the car?

17. Answer: Speed = distance ÷ time Speed = 300km ÷ 6 hours
Speed = 50km/hr

18. More practice
1. How far can a plane travel if it flies 800km/hr for 9 hours?
2. How long does it take a ship to go 500 km if it travels at a speed of 50km/hr?

19. Answer
1. D S T D km ▪ 9hrs = 7200km hr

20. Answer
2. D S T T 500km ÷ 50km = 10 hrs hr

21. Change your answer to mi/hr!
0.67mi/min x 60min/hr =
40 mi/hr

22. Graphing Speed

23. Distance-time graphs
D (m) T (sec)
0 0
5 7

24. Distance (m)
time (sec)

25. Was your graph a straight line?
A distance-time graph which is a straight line indicates constant speed.
In constant speed, the object does not speed up or slow down. The acceleration is zero.

26. Graph the following on a distance-time graph:
D (m) T (s)
0 0
5 1
20 2
45 3
80 4

27. Distance (m)
time (sec)

28. Was your graph a curve?
A graph that curves on a distance-time graph shows that the object is accelerating

29. Distance-time graphs Describe the motion of the object as shown in the
From 0-8 sec, constant speed:
(25 m/sec);
From 8-12 sec, no motion;
From sec, acceleration;
From sec, constant speed

30. 10-3 Notes Acceleration

31. Common Units for Acceleration: m/s2, km/hr2, cm/s2
Acceleration – the rate at which your speed/velocity increases or decreases.
How to calculate acceleration
a= Vf –Vi t
- Vf = final velocity
- Vi = initial velocity
- t = total time
Common Units for Acceleration: m/s2, km/hr2, cm/s2

32. Acceleration Change in velocity Acceleration = ∆V/ ∆T ∆V
Can be change in speed or direction
Acceleration = ∆V/ ∆T ∆V
a t

33. Acceleration Examples-
Ex 1 A deer begins to run from a speed of 0 m/s and increases his speed to 10 m/s in about 15 seconds. What was his acceleration? LF: G: R/F: S:

34. Acceleration Examples-
Ex 2 The train started from rest and over a period of 1 hour it increased speed to 60 km/hr as it left the town. What was the train’s acceleration? LF: G: R/F: S:

35. Acceleration Examples-
Ex. 3 When the bullet left the gun it was traveling at 400 m/s and 5 seconds later it was traveling at a speed of 150 m/s before it slammed into a tree. What was the bullet’s acceleration? LF: G: R/F: S:

36. Acceleration Examples
Ex 4. During a 16 s race, the sprinter accelerated from 2.0 m/s to 6 m/s. What was her acceleration? LF: G: R/F: S:

37. Acceleration problem
A roller coaster’s velocity at the top of a hill is 10m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26m/s. What is the acceleration of the roller coaster?

38. Answer Acceleration = ∆V/ ∆T a = 26m/s – 10m/s 2 s a = 16m/s 2s
a = 8m/s/s or 8m/s2

39. More acceleration problems
1. A car accelerates at a rate of 20mi/hr/s. How long does it take to reach a speed of 80 mi/hr?
2. A car travels at 60 miles per hour around a curve. Is the car accelerating?
3. A car travels in a straight line at 60mi/hr. Is the car accelerating?

40. Answers:
1. ∆V 80mi/hr a t 20mi/hr/s t 4sec = t 2. yes! Because it’s changing direction! 3. no! It’s not changing speed or direction!

41. Deceleration Negative acceleration
Example: A car slows from 60mi/hr to 20mi/hr in 4 seconds. What is its acceleration?

42. Answer: Acceleration = ∆V/ ∆T Acceleration = Vf – Vi t
a = 20mi/hr – 60mi/hr
4 s
a = -40mi/hr 4s
a = -10mi/hr/s

43. Review: Distance-time graph of acceleration

44. Distance-time graph of deceleration

45. Review:Speed-time graph of acceleration

46. Review: Speed-time graph of deceleration

47. Review: Distance-time graph of constant speed

48. Speed-time graphs
Using the distance-time graph from the last frame, draw a speed time graph. First fill in the table below:
Average Speed (m/s) Time (sec)
____ 0 to 8
____ 8 to 12
____ 12 to 20 25
37.5

49. What does your graph look like?
Constant speed will be a horizontal line on a speed time graph.
If the speed decreases, the line will slant down.
If the speed increases, the line will slant up.

50. What do the following speed-time graphs depict?

51. Calculate Acceleration
Initial Velocity
Final Velocity
Time
Acceleration 1.
0km/hr
24km/hr 3s 2.
0m/s
35m/s 5s 3.
20km.hr
60km/hr
10s 4.
50m/s
150m/s 5.
25km/hr
1200km/hr
2min

52. Practice Problems 1. A car accelerates from standstill to 60km/hr in 10s. What is its acceleration? 2. A car accelerates from 25km/hr to 55km/hr in 30 s. What is its acceleration ?

53. A train is accelerating at a rate of 2km/hr/s
A train is accelerating at a rate of 2km/hr/s. If its initial velocity is 20km/hr, what is its velocity after 30s? 4. A runner achieves a velocity of 11.1m/s 9s after he begins. What is his acceleration? What is his distance?