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Saturday, 21 March 2015

interpretation of displacement -time graphs



Displacement-time graph of various types of motion of a body:


Case-1:
Description of motion: For a stationary body, the displacement- time graph is a St. line
                                                         AB parallel to time axis. The graph for such a motion would be 





Interpretation: The slope of st. Line AB (representing instantaneous velocity) is zero, i.e., 
                                     velocity is zero.

Case-2

Description of motion: When .a body, is moving with a zero acceleration or a constant
                                                        velocity, then displacement- time graph wall be 
                                                        (i) a St. line OA, inclined to time axis if the body has zero initial
                                                            displacement 
                                                        (ii) a St. line BC if body has initial displacement x, where OB = x

                                                          The graph for such a motion would be 



Interpretation: Greater is the slope of St. Line OA, higher will be the velocity, i.e., velocity is 
                                    constant.

Case-3:

Description of motion: When a body is moving with a constant acceleration, the
                                                         displacement- time graph is a curve with bend upwards.
                                                         (1) The curve OA corresponds to zero initial displacement curve,
                                                               BC corresponds to initial displacement x.

                                                            The graph for such a motion would be 



Interpretation: The slope of time-displacement curve (i.e. instantaneous velocity) increases 
                                     with time, i.e., velocity is increasing with time.

Case-4:

Description of motion: When a body is moving with a constant retardation, the 
                                                         displacement- time graph is a curve with bend downwards.

                                                          The graph for such a motion would be


Interpretation: The slope of time-displacement curve (i.e. instantaneous velocity) decreases
                                      with time, i.e., velocity is decreasing with time.

Case-5:

Description of motion: When a body is moving with infinite velocity, the
                                                         displacement-time curve is a St. line AB parallel to displacement 
                                                          axis.

                                                          The graph for such a motion would be


Interpretation: Such motion of a body is never possible as velocity is infinity.

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