Distance-Time Graphs

• What do distance-time graphs allow us to visualize?

  How far something has traveled over time
• How far did the cyclist travel in the example?

  50 meters
• What does the gradient of the line on a distance-time graph represent?

  The speed of the object at that time
• What is the formula for speed in terms of distance and time?

  Speed = change in distance / change in time
• What is the speed of the cyclist in the first section of the journey?

  10 meters per second
• What does a flat line on a distance-time graph indicate?

  The object is stationary
• What does a steeper line on a distance-time graph indicate?

  The speed is increasing
• What does a decreasing gradient on a distance-time graph indicate?

  The object is decelerating
• How can you find the speed at a specific point on a curve in a distance-time graph?

  Draw a tangent to the curve at that point
• What is a tangent in the context of a distance-time graph?

  A straight line touching the curve at one point
• How do you calculate the gradient of the tangent?

  Change in distance divided by change in time
• What was the calculated speed at eight seconds in the example?

  4 meters per second
• What do straight lines, flat lines, and curved lines represent on a distance-time graph?

  • Straight lines: Constant speeds
  • Flat lines: Stationary
  • Curved lines: Changing speeds
• What should you do to calculate speed at a point on a straight line?

  Calculate the gradient of the line
• What should you do to calculate speed at a point on a curve?

  Draw a tangent and calculate its gradient
• What is the key takeaway about distance-time graphs?

  Gradient indicates speed at any point