Velocity Time Any lines above the x-axis represent positive velocities, (regardless of their slope). positive velocities Lines below the axis represent negative velocities. negative velocities The slope of a straight line representsacceleration. Velocity-Time Graphs

For each of the following graphs, describe the motion that is taking place: a) Velocity Time positive velocitypositive velocity positive accelerationpositive acceleration b) Velocity Time positive velocitypositive velocity negative accelerationnegative acceleration

c) Velocity Time d) Velocity Time e) Velocity Time f) Velocity Time neg velneg vel neg accelneg accel neg velneg vel pos accelpos accel neg velneg vel zero accelzero accel Pos, then neg velPos, then neg vel Neg accelNeg accel

To Summarize: How to find... from a v-t graph: Instantaneous Velocity 1. Instantaneous Velocity -Read off graph. Instantaneous Accleration 2. Instantaneous Accleration -Slope of straight line. Average Acceleration 3. Average Acceleration - (This is the accel between two points in time) Draw a line between the two points. Find the slope of this line.

Displacement - 4. Displacement - Determine the area between the line and the x-axis. Any areas above the x-axis are positive displacements. Areas below are negative displacements. Velocity Time + - Add the positive and negative areas together.

Distance 5. Distance -Same as displacement, but all areas are positive. Average Velocity 6. Average Velocity - Displacement divided by time. Average Speed 7. Average Speed - Distance divided by time. Example #1 Example #1