1-Dimensional Kinematics
Negative Velocity and Positive
Acceleration
Observe that the object below moves in the negative direction with
a changing velocity. An object which moves in the negative direction
has a negative velocity. If the object is slowing down then its
acceleration vector is directed in the opposite direction as its
motion (in this case, a positive acceleration). The "ticker tape"
shows that each consecutive dot is not the same distance apart (i.e.,
a changing velocity). The position-time graph shows that the slope is
changing (meaning a changing velocity) and negative (meaning a
negative velocity). The velocity-time graph shows a line with a
positive (upward) slope (meaning that there is a positive
acceleration); the line is located in the negative region of the
graph (corresponding to a negative velocity). The acceleration-time
graph shows a horizontal line in the positive region of the graph
(meaning a positive acceleration).
For more information on physical descriptions of motion, visit
The Physics Classroom Tutorial.
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