1. Warm Up
Describe your location in the classroom using specific reference points around you that someone could use as directions to find you if they walked in the room.

2. Unit 2 Motion, Force and Newton’s Laws

3. Motion
How do we know an object is in motion??

4. In the example, how did you know the object was in motion?
Motion: when an object changes position over time relative to a reference point.
Reference Point: the object that appears to stay in one place as another object moves.
Trees and building are reference points that we use on a daily basis.

5. More on reference points…
Do you think a moving object could be used as a reference point?
Yes, we may use a moving object to describe an object that is moving faster than the moving reference point.
Such as a car speeding by a bicyclist.

6. Speed
Speed: the distance traveled by an object divided by the time taken to travel that distance.
What are some units of speed you use?
m/h, ft/s
What are some SI units of speed?
km/h

7. Average speed = total distance
Generally objects do not travel at a constant speed. We have a formula for calculating average speed.
Average speed = total distance
total time

8. You Try… Don’t forget FSAU!!!
This weekend I traveled 1,000 kilometers in 2 hours. What was my average speed?
Average speed=total distance/total time
Average speed=1,000 kilometers/2 hours
Average speed=500 km/hr

9. A question…
Sarah leaves Northwestern at 3:00 and travels 10 km in 10 minutes. Jessica leaves at 3:00 and travels 10 km in 5 minutes. Both girls stop moving after 10 km. After 15 minutes are both girls in the same location??
No!! Why not?
Because they left the school an traveled in different directions.

10. Velocity This is the speed of an object in a particular direction.
Velocity MUST include a speed and DIRECTION.
You try…Andrew left northwestern going south. Andrew traveled 50 km in 25 minutes, what is Andrew’s velocity?
2 km/min SOUTH

11. Another example
Danny left for North Georgia at 3:00 pm. He arrived at 9:00 pm. The distance from Northwestern to North Georgia is 100 miles. What was Danny’s velocity?
Average speed=total distance/total time
Average speed=100 mi/6hr
Average speed=16.66 mi/hr
Velocity= mi/hr north

12. Is velocity constant?
Velocity changes any time the speed or direction of an object changes. Therefore velocity is only constant in a straight line at a constant speed.

13. We speak about velocity everyday… It told us when Ida would arrive!

14. Air traffic control also involves velocity!

15. Combined Velocity
Pretend you are sitting in an airplane traveling 500 mi/hr east. During the flight you decide to use the restroom. You walk to the restroom at a speed of 0.2 mi/hr. While walking to the restroom you have what is called a resultant velocity.
You find this resultant velocity by combining the two velocities.

16. How to calculate resultant velocity
First, we must decide whether the velocities are in the same direction.
If they are you ADD the two velocities to find resultant velocity.
SO, if in your walk to the restroom you are walking in the same direction as the plane what is your resultant velocity?
Resultant velocity=500 mi/hr east mi/hr east
Resultant velocity=500.2 mi/hr east

17. Resultant Velocity Continued
What if the restroom is in the back of the plane and causes you to walk west?
Then you must subtract your walking velocity from the planes velocity
Resultant velocity=500 mi/hr east – 0.2 mi/hr west
Resultant velocity=499.8 mi/hr east

18. Warm Up
It took Ashley 10 hours to get to Tampa, Florida. This distance is about 600 miles south. What was Ashley’s velocity?
S=D/T
S=600 miles/10 hours
S=60 mi/hr
Velocity = 60 mi/hr south

19. Warm Up
The train left the station moving at a velocity of 200 m/sec west. After 30 seconds the train was moving at a velocity of m/sec. What is the trains acceleration?
a=fv-sv/t
A=1400 m/sec-200 m/sec/30sec
A=1200 m/sec/30sec
A=40 m/s² west

20. Acceleration This is the rate at which velocity changes.
Something that is accelerating is . . .
speeding up

21. Acceleration is
slowing down . .
. . . or . . .
changing direction !

22. Formula for determining Acceleration is . . .
Final velocity – Original velocity Time
Acceleration =
Hey Let’s calculate acceleration !!!
At point A, a runner is jogging at 3 m/s. Forty seconds
later, at point B – on a hill – the jogger’s velocity is
only 1 m/s.
What is the jogger’s acceleration from point A
to point B?

23. You’re right!
Answer: m/s/s
1 m/s – 3 m/s
40 secs
-2 m/s
40 secs
Acceleration = = =
0.05 m/s/s
Reason for the m/s/s this means that for every second, the jogger’s decelerates 0.05 m/s.
Negative acceleration (decrease in speed) is called deceleration.
Deceleration example

24. Another deceleration example . . .
roller coaster
climbing a hill !

25. Other deceleration examples:
“Pathfinder’s” landing on Mars
parachutes

26. This occurs because the direction is continuously changing.
Circular motion
(changing direction) involves the continuous changing of the velocity.
This occurs because the direction is continuously changing.
An object in circular motion is accelerating even though its speed may be constant.
Examples include
Ferris Wheel
. . . and . .

27. Which ends our notes covering . . .
the bicycle !
Which ends our notes covering . . .
“Motion” !

28. TOTD – Motion – 11/15/11
What additional information does velocity give you that speed does not?
What types of things can happen to motion to cause acceleration.
A runner starts out a race going 150 m/min. After 5 min she increases her speed to 200 m/min. What is the runners acceleration?

29. Math in Science Activity !!!
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
1. A car travels 240 kilometers in 3 hours. What is the speed of the car during that time?
2. The speed of a cruise ship is 50 kilometers per hour. How far will the ship travel in 14 hours?

30. Math in Science Activity !!! continued
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
3. If a train is traveling 100 kilometers an hour, how far will it go in 5 hours?
4. If a train travels 320 kilometers in 4 hours, what is the speed?

31. Math in Science Activity !!! continued
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
5. If a motorboat travels 25 km/hr down a river whose velocity is 4 km/hr, what is the boats actual velocity?
6. What is the average speed of a jet plane that flies 7200 km in 9 hours?

32. 7. What was Alex’s speed from T=5 sec to T=10 sec?
Problems 7 and 8 refer to the table below, which summarizes Alex’s ride on his new skateboard.
Time (sec) Distance (m)
7. What was Alex’s speed from T=5 sec to T=10 sec?
8. What was Alex’s average speed for the entire ride?

33. Math in Science Activity !!! continued
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
9. Tommy walks 10 blocks to a friends house. (assume all the blocks are equal length). How long will it take Tommy to reach the friend’s house if he walks 3 blocks in 2 minutes?
10. If the average speed of a car is 45 km/hr, how far can it travel in 40 minutes?

34. Math in Science Activity !!! continued
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
An Amtrak train is traveling at a speed of
97 k/hr. A woman on the train realizes she left
her purse in the front car of the train. She
begins running from the back of the train at a
speed of 4 km/hr to the front of the train. How
fast is the woman going?

35. Math in Science Activity !!! continued
“Speed, Distance, Time, and Velocity”
Distance
Speed
Distance
Time
Time =
Speed =
Distance = Speed X Time
12. Here’s a “tricky” one for you!
Sally ran 90 meters for 35 seconds to catch up with her dog Penny. When she got to her dog, she played with her for 70 seconds before they walked back in 75 seconds. Did Sally travel at a constant speed?
What was Sally’s average speed?