2. Velocity vs. Time Analysis of a Velocity vs. Time graph

3. Velocity vs. Time Graphs Constant velocity Constant positive acceleration

4. Velocity vs.Time graphs Constant negative acceleration Constant negative acceleration but object has changed direction (WHY?)

5. Slope of a V vs. T Graph Rise / Run On a velocity vs. time graph Rise = Δv = v f - v i Run = Δt = t f - t i Slope = Δv / Δt… Average Acceleration (a ave )

6. Using slope to predict motion On a velocity vs. time graph  If slope is 0, then acceleration is 0. The velocity is constant.  If slope is positive, acceleration is constant.  If slope is negative, acceleration is constant in the opposite direction.

7. Is the object changing speed? You must consider both the direction of the velocity and the direction of the acceleration. If velocity and acceleration are in the same direction object is speeding up. If the velocity and acceleration are in opposite directions object is slowing down.

8. Speeding up v t Is the velocity positive or negative? Is the acceleration positive or negative? +v -v +a -a The sign for a and v are the same so both objects are speeding up!

9. Slowing down (deceleration) v t Is the velocity positive or negative? +v -v Is the acceleration positive or negative? +a -a The sign for a and v are opposite so both objects are slowing down!

10. Finding Displacement Equal to the “area under the curve” on a v vs. t graph Triangle A = ½ b×h Rectangle A = l×w Base and length are measured in s. Height and width are measured in m/s. Area = (m/s)(s) = m

11. V (m/s) t (s) 50 -25 1 2 3 4 5 6 7 Area = l × w length = 3 s width = 50 m/s 3s × 50 m/sΔd=150 m

12. Velocity vs. Time Graphs The slope of the line tells you the ____________ of the object. The “area under the curve” represents the change in position or ____________of an object. accelerationdisplacement

13. Time to Practice Physics Book - Pg. 93 Practice Problems (13,15,16a) Section Review (1,2,4)