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Acceleration- Change in Velocity. occurs when an object ______________ in speed . occurs when an object _____________________. occurs when an object __________ in speed. Types of acceleration. Increasing speed Example: Car speeds up at green light Decreasing speed
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Acceleration- Change in Velocity • occurs when an object ______________ in speed. • occurs when an object _____________________ • occurs when an object __________ in speed.
Types of acceleration • Increasing speed • Example: Car speeds up at green light • Decreasing speed • Example: Car slows down at stop light • Changing Direction • Example: Car turns screeeeech
Question 1 • How can a car be accelerating if its speed is a constant 65 km/h? _______________________________________ _______________________________________
Calculating Acceleration Acceleration = Final speed – Initial speed Time
Calculating Acceleration Acceleration = 16m/s - 0m/s 4s Acceleration = _______ 1 s 2 s 3 s 4 s 0 s 4 m/s 12 m/s 16 m/s 0 m/s 8 m/s
Question 2 • A skydiver accelerates from 20 m/s to 40 m/s in 2 seconds. What is the skydiver’s average acceleration? a = m/s – m/s s a = ____ a = __________
Graphing Acceleration • Can use 2 kinds of graphs • Speed vs. time • Distance vs. time
Graphing Acceleration:Speed vs. Time Graphs • Speed is increasing with time = accelerating • Line is straight = acceleration is constant
Graphing Acceleration:Speed vs. Time Graphs Rise = 4 m/s Run = 2 s • In Speed vs. Time graphs: • Acceleration = Rise/Run • = 4 m/s ÷ 2 s = ________
Graphing Acceleration:Distance vs. Time Graphs Curved line means the object is accelerating. Your speed is increasing. Remember slope = speed.
Question 3 Run = 3 s Rise = -6 m/s How is the speed of the car changing? (speeding up, slowing down, or staying the same) __________________________ 2) What is this car’s acceleration? __________
Question 4 • Which line(s) represents an object that is accelerating? ________________________________ • Which line(s) show positive acceleration? • ________________________________ • 3) Which line(s) show negative acceleration? • ________________________________ • 4) Which line(s) show constant acceleration? • _________________________________