Friday, June 14, 2013


Describing Motion with Position vs. Time Graphs 

-Motion of objects in 1-dimensional kinematics can be represented by words, diagrams, numbers, equations and  graphs.

-The specific features of the motion of objects are demonstrated by the shape and the slope of the lines on a position vs. time graph.

-The slope of the line reveals useful information about the velocity of the object.

-As the slope goes, so goes the velocity. 

-If the velocity is constant, then the slope is constant (i.e., a straight line). 

-If the velocity is changing, then the slope is changing (i.e. a curved line). 

-If the velocity is positive, then the slope is positive (i.e., moving upwards and to the right).    

-Consider a car moving with a rightward (+). The position vs. time graphs for constant velocity and changing velocity (acceleration) - are depicted as follows.

       Constant Velocity                                            Positive Velocity                                                   
           Positive Velocity                                             Changing Velocity (acceleration)



            Slow, Rightward(+)                                          Fast, Rightward(+)
            Constant Velocity                                           
Constant Velocity



       Slow, Leftward(-)                                             Fast, Leftward(-)
          Constant Velocity                                            Constant Velocity



      Leftward (-) Velocity                                           Leftward (-) Velocity                                       
         Slow to Fast (accelerate)                                   
Fast to Slow (decelerate)


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