Kinematics

Content

• Speed, velocity and acceleration
• Graphical analysis of motion
• Free-fall
• Effect of air resistance

Speed

• Speed is the distance moved per unit time.
• The SI unit of speed is metres per second (m/s)
• Speed = Distance / Time
• Speed = Gradient of distance-time graph
• Speed is a scalar quantity; it has only magnitude, no direction

Velocity

• Velocity is the distance moved in a given direction per unit time, or displacement per unit time.
  
• The SI unit of velocity is metres per second (m/s)
• Velocity = Distance moved in a given direction / Time or Speed = displacement / time
  
• Velocity = Gradient of displacement-time graph
• Velocity is a vector quantity; it has both magnitude and direction

Acceleration

• Acceleration is the change in velocity per unit time.
  
• Acceleration = Change in velocity / Time
• Acceleration = (Final velocity - Initial velocity) / Time
  
• Acceleration = Gradient of velocity-time graph
• Acceleration is a vector quantity; it has both magnitude and direction
• The SI unit of acceleration is metres per second square (m/s²)

Distance-Time Graph

• Speed, v = Gradient of the distance-time graph

• Gradient = y / x = speed