movement and position

• What does a distance-time graph show?

  Distance varies over time for an object

  
• What does a straight line on a distance-time graph represent?

  Constant speed of the moving object

  
• What does the slope of a straight line indicate on a distance-time graph?

  The magnitude of the object's speed

  
• What does a very steep slope on a distance-time graph indicate?

  Object is moving at a large speed

  
• What does a shallow slope on a distance-time graph indicate?

  Object is moving at a small speed

  
• What does a flat, horizontal line on a distance-time graph represent?

  Object is stationary (not moving)

  
• How is changing speed represented on a distance-time graph?

  By a curve on the graph

  
• What does an increasing slope on a distance-time graph indicate?

  Speed is increasing (accelerating)

  
• What does a decreasing slope on a distance-time graph indicate?

  Speed is decreasing (decelerating)

  
• What is the formula to calculate speed from a distance-time graph?

  speed = gradient = $\frac{\Delta y}{\Delta x}$

  
• What do $\Delta y$ and $\Delta x$ represent in the speed formula?


  $\Delta y$ is distance change, $\Delta x$ is time change
• How do you calculate the speed of a train from a distance-time graph?

  Calculate the gradient of the line
• What is the distance travelled by the train if it moves 8 km in 6 minutes?

  Convert to standard units: 8000 m, 360 s
• What is the speed of the train if it travels 8000 m in 360 s?

  Speed = $\frac{8000}{360} =$$22.2 \text{ m/s}$
• How long does the student spend reading the book in the example?

  40 minutes
• Which section of the graph represents the student running home?

  Section C represents the student running home
• What is the total distance travelled by the student?

  0.6 km
• What is average speed?

  Distance travelled every second
• Why is average speed often more useful than instantaneous speed?

  It considers total distance and time
• What is the formula for calculating average speed?

  average speed = $\frac{\text{distance moved}}{\text{time taken}}$
• How do you calculate distance moved using average speed?

  distance moved = average speed × time taken
• How do you use a formula triangle for average speed?

  • Cover the variable to calculate
  • Identify multiplication or division
  • Rearrange the equation accordingly

  
• What is the distance travelled by a plane flying at 250 m/s for 2 hours?

  Convert 2 hours to seconds: 7200 s
• How do you calculate the distance travelled by a plane at 250 m/s for 7200 s?

  distance moved = 250 × 7200
• What is the result of the distance calculation for the plane?

  1,800,000 m
• What is acceleration defined as?

  Rate of change in velocity
• What is the formula for calculating average acceleration?

  acceleration = $\frac{\Delta v}{t}$
• How is change in velocity calculated?

  Change in velocity = final velocity - initial velocity

  
• What does positive acceleration indicate?

  Object is speeding up
• What does negative acceleration indicate?

  Object is slowing down (decelerating)
• What is an example of an object accelerating?

  A rocket speeding up
• What is an example of an object decelerating?

  A car slowing down
• What is the formula for change in velocity?

  ∆v = v − u
• What do the variables v and u represent in the change in velocity formula?

  v is final velocity, u is initial velocity
• How is acceleration calculated from change in velocity?

  a = ∆v / t
• What does it mean when an object is accelerating?

  It is speeding up
• What does it mean when an object is decelerating?

  It is slowing down
• What indicates positive acceleration?

  The object is speeding up
• What indicates negative acceleration?

  The object is slowing down
• If a rocket is speeding up, what can we say about its acceleration?

  Its acceleration is positive