1. Motion:speed, velocity, Acceleration

2. Vector vs. Scalar  Scalar is a quantity with magnitude and no direction  Vector is a quantity with both magnitude and direction.  Magnitude: the size or length of a quantity  Examples:  a. 5 m  b. 30 m/sec, East  c. 5 mi., North  d. 20 degrees Celsius  e. 256 bytes  f. 4000 Calories

3. Speed  The ration of the distance an object moves to the amount of time an object moves  The unit is…..  Is Speed a scalar or Vector Quantity?  There are two different types of speed:  Instantaneous speed=a particular instant. (speedometer)  Average speed=computed for an entire trip  formula= v= total distance/total time or d/t

4. Velocity  The speed and direction of the objects motion is the Velocity  Is velocity a scalar or vector quantity  Velocity can change if the object speeds up or slows down. It can also change if it changes directions.  Formula= Problem: 1. A girl ravels 20 miles on her bicycle, the trip takes 2 hours. Express her speed in miles/hour.

5. Velocity problems cont.  2. A trip to cape Canaveral Florida takes 10 hours. The distance is 816 km. Calculate the average speed.  3. How long will your trip take (in hours) if you travel 350 km at an average speed of 80km/hr?

6. Velocity Problems continued:  4. How man minutes will it take for a satellite to travel 450km at a rate of 120km/s?

7. Acceleration  The rate at which velocity changes  Can be described as changes in speed, changes in direction, or changes in both  Acceleration is also a vector  Changes in speed can be both positive or negative acceleration.

8. Acceleration Continued  Constant speed means that there was no acceleration.  Free fall is also a type of acceleration where the acceleration is 9.8m/s 2 …why is this a constant rate and what do we call this.  a=  Changes in direction are also changes in acceleration.

9. Practice acceleration Problems  1. The space shuttle releases a space telescope into orbit around the earth. The telescope goes from being stationary to traveling at a speed of 1700m/s in 25 seconds. What is the acceleration of the satellite?  2. A ball is rolled at a velocity of 12m/sec. after 36 seconds, it comes to a stop. What is the acceleration of the ball?

10. Acceleration problems continued:  3. A meteoroid changed velocity from 1.0 km/s to 1.8 km/s in 0.03 seconds. What is the acceleration of the meteoroid?  4. A ball rolls down a ramp for 15 seconds. If the initial velocity of the ball was 0.8 m/s and the final was 7m/s what was the acceleration of the ball in minutes?

11. Graphs  Where do time and distance go in velocity graphs?  What about acceleration?  What doe positive velocity graphs look like?  What about acceleration?  What about negative graphs?  How do you know if there is no acceleration when looking at a graph of velocity?