Speed and Velocity

1. Speed and Velocity What’s the deal?

2. Speed and Velocity • Speed • The distance covered per amount of travel time • Speed = Distance covered Travel time • Example • If a bicyclist covers 20 kilometers in 1 hour, her speed is 20km/h. • What if she runs 6 meters in 1 second? • ??? • In science, the preferred unit of speed is meters per second (m/s)

3. Instantaneous Speed • The speed at any instant is the instantaneous speed

4. Average Speed • Average Speed = Total Distance covered Total travel time • What is the average speed of a cheetah that sprints 100 m. in 4 seconds, stops for 10 seconds, and then sprints 200 m. in 10 seconds?

5. If you drove a car for 4 hours at 80 km. per hour, then stopped at the loo for 1 hour, what is your average speed?

6. Velocity • Is when we know both the speed and direction. • For example, if a vehicle travels at 60km/h, do we know the velocity? • How about if we say it moves at 60km/h to the north – do we know the velocity?

7. Speed vs. Velocity • Speed is a description of how fast. • Velocity is a description of how fast AND in what direction. • What is another word we could use to describe velocity? Think back to what we have already learned. (HINT: Arrows)

8. Constant Speed vs. Constant Velocity • Constant speed means steady speed, neither speeding up nor slowing down. • Constant velocity means steady speed AND direction

9. Determine if the following statements are speed or velocity… • A cruise ship traveling at 60 knots south. • ? • A cyclist going 10 mph. • ? • A downhill skier going 40mph. • ? • A person walking 4mph on a treadmill. • ? • A jet traveling 600mph taking-off headed northeast. • ?