Speed and Velocity What is motion? Answer  Motion occurs when an object changes its location in space over a period of time. Did you know that you are spinning 1600 km/hr (1000 miles/hour) while you are sitting in this classroom? Do you feel dizzy? Probably not. The reason you are not dizzy is that motion can only be detected relative to a FRAME OF REFERENCE such as some other object or point in space. The most common frame of reference is the EARTH.

Speed Definition and Formula Distance traveled over a period of time. Formula: Speed = Distance Time Units: m/s or km/hr or miles/hr Round to the nearest tenth!

Example #1 Mr. Lamberton on a bad day, can pitch a baseball from the mound to home plate, a distance of about 20 meters in 0.624 seconds. How fast is his pitch? Speed = distance time Speed = 20 meters 0.624 sec Speed = 32.1 m s

Example #2 Mrs. Kerr walks home from school at a speed of 1.25 m/s. If it takes her 6 minutes (360 seconds) to walk home, how far away is her house? Speed = distance time Speed x time = distance 1.25 m x 360 seconds = 450.0 meters s

Example 3 An attacking hawk has a speed of 100 m/s. How much time did it take the hawk to get dinner if he was flying at an altitude of 50 meters when he spotted a mouse scampering on the ground? Speed = distance time Time = distance speed Time = 50 meters 100 m s Time = 0.5 seconds

Constant Speed Graphing Speed (distance and time increase as an even proportion)

Graphing Speed Stopped (distance stays the same while time continues)

Acceleration Graphing Speed (as time continues, distance INCREASES rapidly)

Deceleration Graphing Speed (as time continues, distance DECREASES rapidly)

Velocity Definition and Formula Round to the nearest tenth! Definition: Distance traveled over a period of time. What makes velocity different from speed is that you must have a DIRECTION. Formula: Speed = Distance Time Units: m/s or km/hr or miles/hr Example: If you walk 4 km/hr in an easterly direction your velocity would be 4 km/hr EAST!

Example 1 Bob ran a marathon (26 miles) in 4 hours, what was his average speed? (Use speed formula) Speed = distance time Speed = 26 miles 4 hours Speed = 6.5 miles hr

Example 2 Jill drove her car 10 hours due South and traveled 800 miles, what was her average velocity? (Use speed formula) Velocity = distance time Velocity = 800 miles 10 hours Velocity = 80.0 miles hr SOUTH

Example 3 A racecar completed a 500-mile race in 4 hours, what was the average speed of the car? (Use speed formula) Speed = distance time Speed = 500 miles 4 hours Speed = 125.0 miles hr