ACCELERATION acceleration – the rate of change in velocity
ACCELERATION positive acceleration – occurs when an object speeds up negative acceleration occurs when an object slows down
GRAPHING VELOCITY VS. TIME Graphing velocity vs. time shows acceleration. Time = independent variable = X -axis Velocity = dependent variable = Y-axis
GRAPHING VELOCITY VS. TIME What is the velocity at 15 s?
GRAPHING VELOCITY VS. TIME What is happening to the acceleration between 0 s and 5 s?
GRAPHING VELOCITY VS. TIME What is happening to the acceleration between 5 s and 10 s?
GRAPHING VELOCITY VS. TIME What is happening to the acceleration between 10 s and 15 s?
GRAPHING VELOCITY VS. TIME What is happening at a time of 25 s?
CALCULATING ACCELERATION a = ΔV t 2 a = acceleration (m/s ) ΔV = change in velocity (m/s) t = time (s)
PRACTICE PROBLEM #1 While participating in the "Tractor Race Finals", Bob accelerates his tractor from rest to a speed of 18 m/s in 6 s. What is his acceleration?
PRACTICE PROBLEM #2 A bug moves down the hall at 1. 2 m/s. When he sees the janitor coming, he begins to run. After 3. 2 s, he is moving at 3. 6 m/s. What is his acceleration?
PRACTICE PROBLEM #3 Jenny spent too much time fixing her hair and is late for the bus. She runs 18 m/s to catch it, but realizes she can't make it. She slows down and stops in 4. 5 s. Calculate her acceleration.