Speed

• What is the difference between distance and displacement?

  Distance is a scalar quantity and only has a magnitude (size)

  Displacement is a vector quantity so it has both magnitude and direction
• What is the difference between speed and velocity?

  Speed is a scalar quantity so only has magnitude (size) whereas velocity is a vector quantity and has magnitude and direction
• What factors can affect the speed at which someone walks, runs, or cycles?

  Their age, fitness, terrain and distance travelled
• What is the typical speed for a person walking?

  1.5m/s
• What is the typical speed for a person running?

  3.0m/s
• What is the typical speed for a person cycling?

  6.0m/s
• What are the typical speeds of a car and a train?

  Car is 13-30m/s

  Train is 50m/s (respectively)
• What is the typical speed for sound travelling in air?

  330m/s
• What is acceleration?

  The change in velocity of an object per second
• What is the unit of acceleration?

  m/s^2
• How can an object be accelerating even if it is travelling at a steady speed?

  If it is changing in direction
• What is happening to an object if it has a negative acceleration?

  it is slowing down (it is called deceleration)
• What info does the gradient of the line in a distance-time graph give?

  Speed
• What info does the gradient of the line in a velocity-time graph provide?

  Acceleration
• How can the distance travelled by an object be found from its velocity-time graph?

  Calculate the area under the graph
• What is the name for the steady speed a falling object reaches when the resistive force is equal to its weight?

  Terminal velocity
• What is the general name for the frictional forces an object experiences when moving through a fluid (liquid or gas)?

  Drag
• In which direction does the drag always act?

  In the direction opposite to which it is moving
• What happens to the drag on an object as its speed increases?

  The drag increases
• What can be done to reduce the drag on an object?

  Streamlining