distance-time graphs

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


  They allow us to visualize how far something has traveled in a certain period of time.
• How far did the cyclist travel in the example given?

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


  The gradient represents 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 during the first section of the journey?


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


  A flat line indicates that the object is stationary.
• What does a steeper line on a distance-time graph indicate?


  A steeper line indicates that the speed is increasing.
• What does a decreasing gradient on a distance-time graph represent?


  A decreasing gradient represents deceleration.
• How can you find the speed at a particular point on a curve in a distance-time graph?


  You need to draw a tangent to the curve at that point.
• What is a tangent in the context of a distance-time graph?


  A tangent is a straight line that has the same gradient as the curve at the point where they touch.
• How do you calculate the gradient of the tangent to find speed?


  By dividing the change in distance by the change in time between two points on the tangent.
• 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 represent constant speeds.
  • Flat lines mean stationary.
  • Curved lines represent changing speeds.
• What should you do to calculate the speed at a point on a straight line?


  You calculate the gradient of the line by dividing the change in distance by the change in time.
• What should you do to calculate the speed at a point on a curve?


  You need to draw a tangent to the curve at that point and calculate the gradient of that tangent.
• What are the key points to remember about distance-time graphs?

  • Gradient = velocity
  • Straight lines = constant speed
  • Flat lines = stationary
  • Curved lines = changing speed
  • Use tangent for speed on curves