1. Bellringer  Study for your quiz on simple machines.  When you finish turn in your paper in the basket.  Get out paper to take notes on. Title the notes Speed and Velocity.  Make sure you have a pen or pencil to write with.

2. Speed and Velocity

3.  Speed  1. Definition: Rate at which an object moves  2. Formula: Distance divided by time (d/t)  3. Units: m/s or km/s

4. Speed- Distance an object travels per unit of time Relationships between speed, distance, and time: Speed = Distance/ Time = d/ t Constant Speed- speed does not change over time Average Speed- speed of motion when speed is changing Avg Speed = Total Distance/ Total Time Time- how long it takes measured in min, sec, hours, etc.

5. Distance  Distance (d) – how far an object travels. –Does not depend on direction.  Imagine an ant crawling along a ruler.  What distance did the ant travel? –d = 3 cm cm 01234567891010

6. Speed  A car drives 100 meters in 5 seconds.  What is the car’s average speed? –s = d/t –s = (100 m) / (5 s) = 20 m/s 100 m 1 s2 s3 s4 s5 s

7. Speed  A racecar is traveling at 85.0 m/s. How far does the car travel in 30.0 s?

8.  Speed  6. Graphs: –Time: x-axis –Distance: y-axis –Constant speed –Changing speed

9. Graphing Motion  Graph distance on the y-axis and time on the x-axis Slope = rise = distance = speed run time run time

10.  Velocity  1. Definition: Describes speed plus direction (n, s, e, w)  2. Formula: D/T plus direction  3. Units: m/s or km/s, north, south, east or west

11.  Velocity  4. Velocities can be combined –Add velocities when in same direction –Velocities in opposite direction= subtract

12.  Velocity  5. Graphs: –Time: x-axis –Distance: y-axis –(same as speed graphs but also has direction)

13. Calculating Velocity: Example  If a runner is running east at 10 m/s sec, what is her velocity?  10 m/s east

14. Calculating Velocity: Example  If you are running up an escalator at 2 steps per second and its moving downward at 3 steps per second, what is the total velocity? In what way are you moving?  3-2  -1 (you are actually moving backwards, down the escalator, although you’re running up it)

16. Exit Assignment  Create two sample problems to solve, one for speed and one for velocity. Include an illustration for each problem. Switch papers with the person beside you. Solve their problem and turn the paper in.  *Be sure to put your name on the paper you created and the paper you answered!!!