Velocity-time graphs

• What can the movement of objects be described using?

  Motion graphs and numerical values
• Why are motion graphs and numerical values used?

  To help in the design of faster and more efficient vehicles
• What does a horizontal line on a velocity-time graph indicate?

  • The object is at constant velocity
• What does a sloping line on a velocity-time graph indicate?

  • The object is accelerating
• What does the gradient of a velocity-time graph represent?

  The acceleration of the object
• How is acceleration defined?

  Acceleration is the rate of change in speed (or velocity)
• What is the unit of acceleration?

  Metres per second squared
• How do you calculate acceleration?

  Acceleration = change of velocity ÷ time taken
• What does a positive gradient on a velocity-time graph indicate?

  Velocity is increasing and acceleration is positive
• What does a zero gradient on a velocity-time graph indicate?

  Velocity is constant and acceleration is zero
• What does a negative gradient on a velocity-time graph indicate?

  Velocity is decreasing and acceleration is negative
• What does a stationary object look like on a velocity-time graph?

  It has a gradient of zero and velocity is stationary
• How do you calculate the acceleration of an object from a velocity-time graph?

  Find the gradient of the red line
• If the change in velocity is 10 m and the change in time is 2 s, what is the acceleration?

  5 m/s²
• How can the distance travelled by an object be calculated from a velocity-time graph?

  • By calculating the area under the graph
  • Using geometry if the lines are straight
  • Counting the squares beneath the line if the lines are curved
• How do you find the area of a triangle on a velocity-time graph?

  Area = ½ × base × height
• If the base of a triangle is 4 m and the height is 8 m, what is the area?

  16 m²
• How do you find the area of a rectangle on a velocity-time graph?

  Area = (length) × (width)
• If the length of a rectangle is 6 m and the width is 8 m, what is the area?

  48 m²
• How do you find the total displacement from a velocity-time graph?

  Add the areas of the shapes under the graph
• What is the total displacement if the areas of the triangle and rectangle are 16 m² and 48 m² respectively?

  64 m
• What are the key concepts related to velocity-time graphs?

  • Velocity can be constant, increasing, or decreasing
  • Acceleration can be positive, negative, or zero
  • The area under the graph represents distance travelled