Speed, velocity and acceleration

1.1 Length and time

1.3 Mass, weight and density

Speed, velocity and acceleration

  1. Speed

    1. Speed is the rate of change in distance
    2. Velocity is speed in a specified direction
    3. Mean speed is total distancetotal time
    4. Acceleration is the rate of change in speed

  2. Graphs

    1. A distance/time graph is a graph of distance against time
    2. A speed/time graph is a graph of speed against time
    3. The speed/time graph of a body at rest is a flat line at zero
    4. The speed/time graph of a body moving with constant speed is a flat non-zero line
    5. The speed/time graph of a body moving with changing speed is a non-flat curve
    6. The speed/time graph of a body with constant acceleration is a linear graph with the gradient of the line equal to the acceleration
    7. The area under a speed/time graph is the distance travelled

  3. Free fall

    1. Acceleration of free fall for a body near to the Earth is a constant 10 ms-2 1
    2. Acceleration of free fall for a body in a uniform gravitational field is constant towards the centre of the field
  1. Acceleration is actually variable on the surface of Earth, but is always 9.8 ms-2 to 2 significant figures ↩