Physics

• Topics covered in the final examination in Physical Sciences

  • Vectors in two dimensions
  • Newton's laws and application of Newton's laws
• Resultant


  The vector sum of two or more vectors, i.e. a single vector having the same effect as two or more vectors together
• Determining the resultant of vectors

  1. Find the vertical and horizontal components of each vector

  2. Add co-linear vertical components

  3. Add co-linear horizontal components

  4. Obtain the resultant vertical vector (R) and resultant horizontal vector (R.)

  5. Sketch the resultant vertical vector (R,) and the resultant horizontal vector (R.)
• Calculating the magnitude of the resultant

  Use the theorem of Pythagoras
• Determining the direction of the resultant

  Use simple trigonometric ratios
• Determining the resultant (R) of two vectors

  1. Graphically using the tail-to-head or tail-to-tail method (parallelogram method)

  2. By calculation using the component method
• Closed vector diagram


  A vector diagram where the resultant vector is zero
• Resolving a vector into its horizontal and vertical components

  1. Use R. = R cos θ for the resultant x component

  2. Use R, = R sin θ for the resultant y component
• Normal force (N)


  The force or the component of a force which a surface exerts on an object in contact with it, and which is perpendicular to the surface
• Frictional force (f)


  The force that opposes the motion of an object and which acts parallel to the surface
• Frictional force


  • Proportional to the normal force
  • Independent of the area of the surfaces that are in contact with each other
• Static frictional force (f.)

  The force that opposes the tendency of motion of a stationary object relative to a surface. It can have a range of values from zero up to a maximum value, μ.N.
• If a force, F, applied to an object parallel to the surface, does not cause the object to move, F is equal in magnitude to the static frictional force