# position time graphs

## graphing position and time

The motion of an object can be represented by a position-time graph like Graph 1 in the Figure 1.1. In this type of graph, the y-axis represents position relative to the starting point, and the x-axis represents time. A position-time graph shows how far an object has traveled from its starting position at any given time since it started moving. Q: In the Figure 1.1, what distance has the object traveled from the starting point by the time 5 seconds have elapsed? A: The object has traveled a distance of 50 meters.

## slope equals velocity

In a position-time graph, the velocity of the moving object is represented by the slope, or steepness, of the graph line. If the graph line is horizontal, like the line after time = 5 seconds in Graph 2 in the Figure 1.2, then the slope is zero and so is the velocity. The position of the object is not changing. The steeper the line is, the greater the slope of the line is and the faster the objects motion is changing.

## calculating average velocity from a positiontime graph

Its easy to calculate the average velocity of a moving object from a position-time graph. Average velocity equals the change in position (represented by d) divided by the corresponding change in time (represented by t): velocity = d t For example, in Graph 2 in the Figure 1.2, the average velocity between 0 seconds and 5 seconds is: d t 25 m 0 m = 5 s0 s 25 m = 5s = 5 m/s velocity =

## instructional diagrams

No diagram descriptions associated with this lesson

## questions

a position-time graph shows how far an object has traveled at any given time since it started moving.

``````-->  a. true

b. false
``````

a position-time graph shows the direction(s) the moving object has traveled relative to the starting position.

``````-->  a. true

b. false
``````

the slope of a position-time graph can be used to find the moving objects

``````-->  a) velocity.

b) position.

c) acceleration.

d) none of the above
``````

the steeper the line on a position-time graph, the faster the objects motion is changing.

``````-->  a. true

b. false
``````

what is the formula for calculating the average velocity of a moving object?

``````-->  a) average velocity = d/t

b) average velocity = t/d

c) average velocity = d x t

d) average velocity = d + t
``````

## diagram questions

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