1. Motion and Speed

2. Motion- a change in position. A reference point is needed to know if the position has changed. Speed- the rate of change in position…rate of motion.

3. There are several ways to measure speed. 1.Instantaneous speed- rate of motion at any given instant. Ex: speedometer 2. Constant speed- speed that does not change.

4. 3. Average speed- total distance traveled divided by the total time of travel. This is the best way to describe speed when the rate of motion changes.

5. Speed Equation VariableEnding Units d = distance meter or kilometer t = timesec. or hr. or min. s = speedmeter/sec. or (or v) kilometer/hr.

6. d = s (v) X t t = d / s (v) s (v) = d / t d s (v)t X........

7. Ex: A passenger elevator operates at an average speed of 8 m/s. If the 60 th floor is 219m above the first floor, how long does it take the elevator to go from the first floor to the 60 th floor?

8. Ex: A motorcyclist travels an average speed of 20 km/h. If the cyclist is going to a friend’s house 5 km away, how long does it take the cyclist to make the trip?

9. Ex: Sound travels at a speed of 330 m/s. If a lightning bolt strikes the ground 1km away from you, how long will it take for the sound to reach you? (Watch out for this one!!!)