distance-time graphs

• What should you be able to construct from given information by the end of the video?

  A distance time graph
• What can you determine from a distance time graph?

  An object's speed
• What should higher tier students be able to use to determine the speed of an accelerating object?

  A tangent
• What key fact is mentioned about objects moving in a straight line?

  Distance can be represented by a graph
• How far did the person walk in the first part of the journey?

  100 m
• How long did the person take to walk 100 m?

  100 seconds
• How long did the person stop for during the journey?

  40 seconds
• How far did the person walk in the last part of the journey?

  70 m
• How long did the last part of the journey take?

  50 seconds
• What are the axes of the distance time graph?

  Distance on the y-axis, time on the x-axis
• How do you represent a stop in a distance time graph?

  Place a dot at the same distance
• What does the gradient of a distance time graph represent?

  The object's speed
• How do you calculate the speed from a distance time graph?

  Divide distance traveled by time taken
• What is the speed for the first part of the journey if the distance is 120 m and time is 60 seconds?

  $2 \text{ m/s}$
• What is the speed for the second part of the journey if the distance is 40 m and time is 130 seconds?

  $0.3 \text{ m/s}$
• What does an upward sloping curve on a distance time graph indicate?

  The object is accelerating
• How do you find the speed of an object at a specific point on an accelerating graph?

  Draw a tangent to the line
• If the distance at 100 seconds is 140 m and the time taken is 80 seconds, what is the speed?

  $1.75 \text{ m/s}$
• What are the steps to plot a distance time graph for a journey?

  1. Place a dot at (0 m, 0 seconds).
  2. Place a dot at the distance and time for the first part.
  3. Place a dot for any stops at the same distance.
  4. Place a dot for the distance and time for the last part.
  5. Connect the dots with straight lines.
• What are the key differences between speed and velocity?

  • Speed: scalar quantity, only magnitude
  • Velocity: vector quantity, includes direction
• What is the importance of the gradient in a distance time graph?

  • Indicates the speed of the object
• What is the significance of a tangent on an accelerating distance time graph?

  • Determines the speed at a specific point