Effects of forces

1.4.2 Centre of mass

Effects of forces

  1. On a body

    1. A force may produce a change in size and shape of a body

  2. Extension of a spring

    1. An extension/load graphs is a graph of the load on a spring against the extension
    2. Hooke’s law states that extension is directly proportional to tension
    3. F = kx where k is the “stiffness” of the spring
    4. The “limit of proportional” is the point at which Hooke’s law fails and the gradient of an extension/load graph falls

  3. Change in motion

    1. F = ma

  4. Resolving forces in 1 dimension

    1. The resultant force is equal to the sum of the forces in the desired direction minus the sum of the forces in the opposite direction
    2. Curved motion is due to a centripetal force towards the centre of the circle the curve passes through

  5. Turning effect

    1. The moment of a force is its turning effect around a pivot1
    2. There is no turning effect if the sum of clockwise moments around the pivot is equal to the sum of anticlockwise moments around it

  6. Conditions for equilibrium

    1. A system is in equilibrium if there is no resultant force or turning effect
  1. Moment = Force ⋅ Distance ↩