P5b

• What is the unit of speed?

  Metres per second (m/s)
• How is velocity defined?

  Speed in a given direction
• What does acceleration measure?

  The rate of change of velocity
• What is deceleration?

  A negative acceleration; slowing down
• What is the unit of acceleration?

  Metres per second squared (m/s²)
• What characterizes circular motion?

  Constant speed, but changing velocity
• How do you denote initial and final speeds in equations?

  • Use u for initial speed
  • Use v for final speed
• What is the formula for distance in terms of speed and time?

  Distance = speed × time (s = v × t)
• What is the formula for acceleration?

  Acceleration = change in velocity ÷ time (a = Δv ÷ t)
• What is the equation relating final speed, initial speed, acceleration, and distance?

  v² – u² = 2as
• What is the shape of a distance-time graph for a stationary object?

  • Horizontal line
• What does a straight line sloping upwards on a distance-time graph indicate?

  • Object at a steady speed
• What does the gradient of a distance-time graph represent?

  Equals the speed
• What does a horizontal line on a velocity-time graph indicate?

  • Object at a steady speed
• What does a straight line sloping upwards on a velocity-time graph indicate?

  • Object is accelerating
• What does a straight line sloping downwards on a velocity-time graph indicate?

  • Object is decelerating
• What does the gradient of a velocity-time graph represent?

  Equals the acceleration
• What does the area underneath a velocity-time graph represent?

  Equals the distance travelled
• What does the gradient of the tangent to a distance-time graph represent?

  Equals the instantaneous speed
• What is terminal velocity?

  The maximum speed of a falling object
• What happens when an object accelerates?

  The force of air resistance increases
• When is terminal velocity achieved?

  When weight and air resistance balance
• What are typical speeds for walking, running, and cycling?

  • Walking ~ 1.5 m/s
  • Running ~ 3 m/s
  • Cycling ~ 6 m/s
• What is the typical speed of sound in air?

  ~ 330 m/s