Motion Graph Notes

Here is a list of all the things you need to know about linear motion graphs:
• The slope of the displacement graph is the velocity.
• A horizontal line on the displacement graph means displacement staying the same as time goes on, hence standing still, zero velocity.
• A straight line sloping down means position decreasing by a set amount each second, hence walking backwards at a set pace.
• A straight line sloping up means displacement increasing by a set amount each second, hence walking forward at constant velocity.
• If the displacement graph is curving, its slope and hence its velocity are changing - it is accelerating.
• Curving up (increasing slope) is positive acceleration.
• Curving down (decreasing slope) is negative acceleration.
• The slope of the velocity graph is the acceleration.
• A horizontal line on the velocity graph means no change in velocity, hence zero acceleration.
• A line sloping up means positive acceleration, velocity increasing as time goes on.
• A line sloping down means negative acceleration, velocity decreasing as time goes on.
• If a sloped line on the velocity graph goes through zero, the object is momentarily stopped at that time.
• The acceleration graph shows how much the object is accelerating at each time. In problems we deal with in this class, acceleration changes suddenly from one value to another. The object will accelerate at 2 m / s for a certain time, then suddely stop accelerating; there is no gradual change in acceleration.