Objectives:

1
Velocity and Acceleration

• Objectives
• Be able to distinguish between distance and
  displacement
• Explain the difference between speed and velocity
• Be able to interpret motion graphs

2
Vocabulary

• Distance
• Displacement
• Speed
• Average speed
• Instantaneous speed
• velocity

3
Distance and Displacement

• Distance How far an object has moved.
• Measure in Meters (M)
• Displacement the distance and direction of an
  objects change in position from the starting
  point.

4
Speed

• Speed The distance an object travels per unit
  of time.
• Speed Distance (m)
• Time (s)
• Average Speed the total distance traveled
  divided by the total time travel, even if the
  speed was changing.

5
Instantaneous Speed

• Instantaneous Speed the speed at a given point
  in time.

6
Plotting a Distance vs. Time Graph

• Distance is plotted on the vertical axis (y-axis)
• Time is plotted on the horizontal axis (X-axis)
• A horizontal line is a speed of 0 m/s (stopped)
• The slope of the line is equal to the speed of
  the object

7
Velocity

• Velocity includes the speed of an object and
  the direction of its motion.

8
Acceleration

• Objectives
• 1. Identify how acceleration, time, and
  velocity are related
• 2. Explain how positive and negative acceleration
  affect motion
• 3. Describe how to calculate the acceleration of
  an object

9
Acceleration

• Acceleration is the rate of change of velocity.
• Its how fast an object is getting faster
• Acceleration Change in Velocity (m/s)
• time (s)

10
Calculating Acceleration

• First calculate the change in velocity.
• Final Velocity - Initial Velocity
  (Vf - Vi)
• 2. Divide the change in Velocity by the Time of
  the measurements.
• Final Velocity - Initial Velocity (Vf
  - Vi)
• Time t

11
Practice Problem

• What is the acceleration the Fastest Car in the
  World
• Sport 0 to 60 mph in 3.7 seconds

12

• Initial speed 0 m/h
• Final speed 60 m/h
• Time 3.7 seconds 0.00103 hours
• 60 m/h - 0 m/h 58,252 m/h2
• 0.00103 hours
• For every hour this car drives its speed will
  increase by 58,252 m/h

13
Practice Problem for Positive Acceleration

• A jet airliner starts from rest at the end of a
  runway and reaches a speed of 80m/s in 20
  seconds.
• What is its acceleration?
• Initial speed 0 m/s Final speed 80
  m/s t 20 seconds
• 80 m/s - 0 m/s 4 m/s2
• 20 s
• For every second the plane went down the runway
  its speed will increase by 4 m/s

14
Practice Problem for Negative Acceleration

• A skateboarder is moving a constant velocity of 3
  m/s and comes to a stop in 2 seconds.
• What is its acceleration?
• Initial speed 3 m/h Final speed 0 m/s
  t 2 sec
• 0 m/s - 3 m/s - 1.5 m/s2
• 2 s
• For every second the skateboarder slows down he
  will decrease his speed by 1.5 m/s