1. LINEAR MOTION
CHAPTER 2

2. ONE DIMENSIONAL MOTION
SIMPLEST MOTION

3. MOTION IS RELATIVE
OBJECTS MOVE WITH RESPECT TO OTHER OBJECTS OR A FRAME OF REFERENCE
ANY FRAME OF REFERENCE CAN BE USED AS LONG AS IT IS USED CONSISTENTLY. CONSISTANCY IS THE KEY IN ALL MEASUREMENTS.

4. DISPLACEMENT ∆X = Xf – Xi
DISPACEMENT = CHANGE IN POSITION = FINAL POSITION – INITIAL POSITION
NOT ALWAYS EQUAL TO DISTANCE TRAVELED
CAN BE POSITIVE (FORWARD) OR NEGATIVE(BACKWARD)

5. SPEED SPEED IS A MEASURE OF HOW FAST SOMETHING IS MOVING.
IT HAS NO DIRECTION
IT IS CALLED A SCALAR QUANTITY.
SPEED = DISTANCE/TIME
V = D/T
UNITS ARE M/S

6. INSTANTANEOUS SPEED AN OBJECT DOES NOT ALWAYS GO AT THE SAME SPEED.
INSTANTANEOUS SPEED IS THE SPEED AT A MOMENT IN TIME.

7. AVERAGE SPEED
THE AVERAGE SPEED IS THE AVERAGE OF ALL THE SPEEDS TRAVELED DURING THE TRIP.
AVERAGE SPEED = TOTAL DISTANCE
TOTAL TIME

8. PROBLEM SOLVING RECIPE
1. WRITE DOWN WHAT YOU KNOW
2. WRITE DOWN WHAT YOU WANT TO KNOW
3. WRITE DOWN YOUR EQUATION AND REARRANGE IT TO SOLVE FOR YOUR VARIABLE.
4. SOLVE, PLUG AND CHUG!

9. QUESTION
THE SPEEDOMETER IN EVERY CAR ALSO HAS AN ODOMETER THAT RECORDS THE DISTANCE TRAVELED.
IF THE ODOMETER READS ZERO AT THE BEGINNING OF A TRIP AND 35 KM A HALF HOUR LATER, WHAT IS THE AVERAGE SPEED?

10. ANSWER
D = 35 KM
T = .5 H
V = ?
V = D/T
V = 35 KM / .5 H
V = 70 KM/H

11. QUESTION
WOULD IT BE POSSIBLE TO ATTAIN THIS AVERAGE SPEED AND NEVER EXCEED A READING OF 70 KM/H ON THE SPEEDOMETER?
NO! WHY?

12. QUESTION
IF A CHEETAH CAN MAINTAIN A CONSTANT SPEED OF 25 M/S, IT WILL COVER 25 METERS EVERY SECOND. AT THIS RATE, HOW FAR WILL IT TRAVEL IN 10 SECONDS?

13. ANSWER V = 25 M/S T = 10 S D = ? V = D/T VT=D 25 M/S X 10S = D
250 M = D

14. HOW ABOUT IN 1 MINUTE? V = 25 M/S T = 1 MINUTE = 60 S D = ? V = D/T
VT=D
25 M/S X 60S = D
1500 M = D
1.5 KM = D

15. SPEED V.S. VELOCITY SPEED IS THE RATE THAT AN OBJECT MOVES
VELOCITY IS THE SPEED IN A GIVEN DIRECTION
SPEED IS A SCALAR QUANTITY
VELOCITY IS A VECTOR QUANTITY

16. VELOCITY V=∆X = Xf – Xi ∆T = Tf – Ti
AVERAGE V IS THE DISPLACEMENT DIVIDED BY THE TIME INTERVAL.
CAN BE POSITIVE OR NEGATIVE

17. VELOCITY QUESTION
A CAR IS MOVING NORTH AT 60 KM/H. IT PASSES A CAR MOVING SOUTH AT 60 KM/H.
DO THEY HAVE THE SAME SPEED?
DO THEY HAVE THE SAME VELOCITY?

18. CONSTANT VELOCITY VELOCITY HAS TWO COMPONENTS: SPEED DIRECTION
IF EITHER COMPONENT CHANGES THE VELOCITY IS NOT CONSTANT.
IF BOTH STAY THE SAME VELOCITY IS CONSTANT.

19. VELOCITY CAN BE INTERPRETED GRAPHICALLY
THE SLOPE OF THE DISPLACEMENT/TIME GRAPH IS EQUAL TO THE AVERAGE VELOCITY OF THE OBJECT.

20. INSTANTANEOUS VELOCITY
THE VELOCITY AT ANY GIVEN MOMENT
IT MAY NOT BE THE SAME AS AVERAGE VELOCITY.

21. QUESTION IN A CAR THERE ARE THREE CONTROLS THAT CHANGE VELOCITY.
CAN YOU LIST THEM?
GAS PEDAL
STEERING WHEEL
BRAKE

22. ACCELERATION RATE AT WHICH THE VELOCITY IS CHANGING
ACCELERATION = CHANGE IN VELOCITY
TIME INTERVAL
A = ∆V ∆T

23. NEGATIVE ACCELERATION
DECELERATION IS THE COMMON TERM.
ACCELERATION WITH A NEGATIVE VALUE IS THE PHYSICS WAY.

24. ACCELERATION IS A VECTOR QUANTITY
ACCELERATION HAS DIRECTION
ACCELERATION CAN BE CONSTANT
RATE OF INCREASE DOES NOT CHANGE
DIRECTION DOES NOT CHANGE
IF EITHER OF THESE CHANGE ACCELERATION IS NOT CONSTANT.
WHEN ACCELERATION IS CONSTANT YOUR VELOCITY IS NOT CONSTANT.
WHY?

25. WHEN DOES ACCELERATION OCCUR?
ACCELERATION OCCURS WHENEVER THERE IS A CHANGE IN MOTION

26. WHAT ARE THE UNITS? THE UNITS FOR ACCELERATION ARE M/S/S OR M/S2
METERS PER SECOND PER SECOND
WHICH MEANS EACH SECOND THE OBJECTS SPEEDS UP SO MANY M/S.

27. QUESTION
SUPPOSE A CAR MOVING IN A STRAIGHT LINE STEADILY INCREASES ITS SPEED EACH SECOND, FIRST FROM 35 TO 40 KM/H, THEN FROM 40 TO 45 KM/H, THEN FROM 45 TO 50 KM/H. WHAT IS ITS ACCELERATION?
5 M/S2

28. QUESTION
IN 5 SECONDS A CAR MOVING IN A STRAIGHT LINE INCREASES ITS SPEED FROM 50 KM/H TO 65 KM/H, WHILE A TRUCK GOES FROM REST TO 15 KM/H IN A STRAIGHT LINE. WHICH UNDERGOES GREATER ACCELERATION?

29. ANSWER CAR TRUCK T = 5S T = 5 S Vi = 50 KM/H Vi = 0 KM/H
Vf = 65 KM/H Vf = 15 KM/H
A = ? A = ?
A = Vf – Vi T

30. CONT. A car= Vf – Vi A = Vf – Vi T T A car = 65 KM/H – 50 KM/H 5 S
A car = 3 KM/H/S
A truck = 15 KM/H – 0 KM/H
A truck = 3 KM/H/S

31. FREE FALL FREE FALLING OBJECTS UNDERGO CONSTANT ACCELERATION.
CAUSED BY THE EFFECT OF THE GRAVITATIONAL FORCE OF THE EARTH
THE ACCEPTED VALUE= M/S2
WE USE -10 M/S2

32. WHAT GOES UP MUST COME DOWN
OBJECTS THROWN UP IN THE AIR WILL SLOW TO A STOP AND THEN RETURN TO THE EARTH AT THE SAME RATE.
SPEEDS WILL BE THE SAME AT THE CORRESPONDING LOCATIONS ON THE TRIP UP AND DOWN
DIRECTIONS WILL BE DIFFERENT
ACCELERATION WILL BE THE SAME

33. EQUATION ACCELERATION= CHANGE IN SPEED TIME ELAPSED
A = 10 M/S = 10 M/S2
1 S

34. QUESTION
WHAT WOULD THE SPEEDOMETER READING ON A FALLING ROCK BE 4.5 SECONDS AFTER IT DROPS FROM REST?
HOW ABOUT 8 SECONDS?

35. UNIFORMLY CONSTANT ACCELERATION
Velocity (m/s)
Time (s)
WHAT DO YOU OBSERVE ABOUT THE SLOPE?

36. QUESTION
AN APPLE DROPS FROM A TREE AND HITS THE GROUND IN ONE SECOND. WHAT IS ITS SPEED UPON STRIKING THE GROUND?
10 M/S
WHATIS ITS AVERAGE SPEED DURING THE ONE SECOND?
5 M/S
HOW HIGH ABOVE GROUND WAS THE APPLE WHEN IT FIRST DROPPED?
5 M

37. GRAPHING SLOPE OF DISTANCE V.S. TIME GRAPH = VELOCITY
SLOPE OF VELOCITY V.S. TIME GRAPH = ACCELERATION
AREA UNDER THE CURVE OF A VELOCITY V.S. TIME GRAPH = DISPLACEMENT

38. AIR RESISTANCE
SLOWS FALL

39. EQUATION D = 1/2GT2 V = GT JUST FOR PHUN!