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v (m/s). time (s). The object is moving backwards at a constant rate. Then it speeds up, going faster and faster backwards. An object starts from rest from a negative position and moves forward faster and faster. .
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v (m/s) time (s) The object is moving backwards at a constant rate. Then it speeds up, going faster and faster backwards.
An object starts from rest from a negative position and moves forward faster and faster. b) A car is backing up and presses the brake to slow down until it comes to a stop. v (m/s) v (m/s) time (s) time (s)
v v x x t t t t *Stopping* -------------------------------------------------------------------------------------------------------------------------------------------------------- ***
x x x v v v t t t *Turning Around* *** ---------------------------------------------------------------------------------------------------------- ***
Velocity vs. Time Graphs • Above the time axis: moving forward • Below the time axis: moving backwards
v v t t Velocity vs. Time Graphs • Going towards the time axis: slowing down • Going away from the time axis: speeding up
x x x x x x Positive acceleration *Concavity of x-t graphs* Negative acceleration Concave up Concave down