Motion in One Dimension (Position vs.

Time)Chapter 5.1

Distance, Position and Displacement

- Distance The total distance that an object has

moved. - Ex. You walk 3 meters north and then walk 3

meters south. What distance have you traveled? - 6 meters

Distance, Position and Displacement

- Position Where you are relative to a starting

point. - Ex. You walk 3 meters north.
- Your position is 3 meters from your starting

point.

Distance, Position and Displacement

- Displacement A measure in distance relative to a

starting point that includes direction. - Ex. You walk 3 meters north and then 3 meters

south. What is your displacement? - 0 meters.
- Ex. Your walk 3 meters north and 4 meters east.

What is your distance traveled? What is your

displacement? - Distance 7 meters.
- Displacement 5 meters.

Motion of Objects

- To describe the motion of an object, what other

information will we need other than position,

distance or displacement? - Time
- If I have the objects position and time, what

can be determined about the objects motion? - Speed or Velocity

1. Collect Data

2. Choose appropriate axes and plot the data.

3. Draw a curve that provides a best fit to the

points.

What information does the shape of the curve

provide?

- Straight line constant velocity.
- Changing curve changing velocity(i.e.

acceleration).

What information does the shape of the curve

provide?

Negative Acceleration

Positive Acceleration

Decreasing Velocity

Increasing Velocity

Characterize the motion of the object from A to E.

- Constant velocity in the positive direction.
- Decreasing velocity.
- Stationary.
- Increasing velocity.
- Constant velocity in the positive direction.

What information does the slope of the curve

provide?

- Positively sloped curve movement in the

positive direction. - Negatively sloped curve movement in the

negative direction.

What else does the slope tell us?

- What is the motion described by each curve?
- How does the velocity of each curve compare to

one another? - A is stationary
- B is moving at the same
- speed as C, but their starting
- position is different.
- D is moving slower than
- B or C.

Analyzing motion of more than one object.

- Two vehicles travel through a speed trap

traveling at two different velocities.

Determining the slope of the curve.

1997 World Championships - Athens, Greece

Maurice Green

100

90

80

70

60

Distance (m)

50

40

30

20

10

0

0

2

4

6

8

10

Time (s)

Velocity determined from the slope of the curve.

rise run df di tf

ti 85m-50m 8.4s-5.4s m 11.7m/s Since

m v v 11.7 m/s

Key Ideas

- Although space exists in 3 dimensions, analysis

of objects in motion can be limited to one

dimension to simplify problems. - When graphing position vs. time, use the x-axis

for time and the y-axis for position. - By analyzing the shape of a position vs. time

graph, the relative motion of the object can be

determined, i.e. constant velocity, acceleration,

stationary. - The slope of the position vs. time graph provides

the average velocity over the time interval.

What can be inferred from the following graph?