Who’s Faster? Speed = distance/time 180 meters 10 seconds = 180m 18 m/s 10 s 160 meters = 160m 20 m/s 8 seconds 8s
Speed or Velocity?Speed – the rate at which an object moves how fast an object moves 15 m/s (meters per second)Velocity – an object’s speed in a specific direction how fast AND which way an object moves 5 m/s north
Speed or Velocity?20 m/s - Speed17 m/s east - Velocity100 m/s up – Velocity0.15 m/s - Speed
Warm-Up Aug. 26,2011 Fill in the triangle with the formula for speed. What is the velocity of a car thattraveled 252 miles East in 4 hours?
Speed = Distance/Time D S TWhat is the velocity of a car thattraveled 252 miles E in 4 hours? Distance 252 mi. = 63 mph E Time 4 hr.
Acceleration• Acceleration – The rate at which velocity changes A change in velocity (Speed or Direction) Examples: Speeding up- A plane taking off Slowing down- A car stopping at a red light Changing direction – A car turning at a corner
Determining AccelerationAcceleration = final velocity – initial velocity time Vf - Vi A T
Warm-Up Aug. 29,2011 What two factors determine an object’s speed? Distance and TimePractice Problem:What is the velocity of a runner traveling 35 meters North in 7 seconds? Speed = Distance = 35 m = 5 m/s Time 7s