1. Forces and Motion Section1.2: Speed measures how fast position changes.

2. Here’s to Speed…. http://www.youtube.com/watch?v=rw4 eE8RMosQhttp://www.youtube.com/watch?v=rw4 eE8RMosQ

3. Vocabulary Word ______________ is the change of position over time. Motion

4. Vocabulary Word ____________ is a measure of how fast something moves or the distance it moves in a given amount of time. speed

6. 00:00 00:01 00:02 00:0100:02 8 meters 0 m 4 meters How far will each skater travel in five seconds?

7. Calculating Speed S = d t S = speed d = distance t = time

8. A racer completes a 100-meter course in 20 seconds. What is his speed? What do you know? Distance = 100 m Time = 20 s What do you want to find out?speed Substitute into the formula: S = 100 m 20 s Calculate:S = 5 m/s

9. A baseball travels 200 m in 25 s. What is its speed? S = distance time S = 200 m 25 s S = 8 m/s Practice Problem # 1

10. This bunny can travel 100 meters in 50 seconds. What is his speed? S = 100 m 50 s S = 2 m/s Practice Problem #2

11. Vocabulary Word ___________ is a speed in a specific direction. Velocity

12. If two scooters are moving at the same speed but in opposite directions, is their velocity the same? 5 m/s east 5 m/s west NO! Since they have different directions they have different velocities!

13. Green arrows show velocity. A longer arrow indicates a faster speed than does a shorter arrow. The direction of the arrow indicates the direction of motion.

14. Vocabulary Word A _______________ is a quantity that has both size and direction. vector

15. Your dog Sam often runs away from home. You know that he averages 2 kilometers per hour on these adventures. Is that enough information to determine this location when he has been gone for 20 minutes? NO A neighbor calls to tell you that she saw Sam making a beeline north. Now do you have enough information to determine his location? YES – only if he hasn’t changed direction since then.

16. VECTOR http://www.youtube.com/watch?v=A05 n32Bl0aYhttp://www.youtube.com/watch?v=A05 n32Bl0aY