Scalar products

  • Flexi Quads
    problem
    Favourite

    Flexi Quads

    Age
    16 to 18
    Challenge level
    1 out of 3

    A quadrilateral changes shape with the edge lengths constant. Show the scalar product of the diagonals is constant. If the diagonals are perpendicular in one position are they always perpendicular?

  • Cubestick
    problem
    Favourite

    Cubestick

    Age
    16 to 18
    Challenge level
    2 out of 3

    Stick some cubes together to make a cuboid. Find two of the angles by as many different methods as you can devise.

  • Air Routes
    problem

    Air Routes

    Age
    16 to 18
    Challenge level
    2 out of 3
    Find the distance of the shortest air route at an altitude of 6000 metres between London and Cape Town given the latitudes and longitudes. A simple application of scalar products of vectors.
  • Pythagoras on a Sphere
    problem

    Pythagoras on a Sphere

    Age
    16 to 18
    Challenge level
    3 out of 3
    Prove Pythagoras' Theorem for right-angled spherical triangles.
  • Quaternions and Reflections
    problem

    Quaternions and Reflections

    Age
    16 to 18
    Challenge level
    3 out of 3
    See how 4 dimensional quaternions involve vectors in 3-space and how the quaternion function F(v) = nvn gives a simple algebraic method of working with reflections in planes in 3-space.
  • Bond angles
    problem

    Bond Angles

    Age
    16 to 18
    Challenge level
    3 out of 3
    Think about the bond angles occurring in a simple tetrahedral molecule and ammonia.
  • Flexi Quad Tan
    problem

    Flexi Quad Tan

    Age
    16 to 18
    Challenge level
    1 out of 3

    As a quadrilateral Q is deformed (keeping the edge lengths constnt) the diagonals and the angle X between them change. Prove that the area of Q is proportional to tanX.

  • Coordinated crystals
    problem

    Coordinated Crystals

    Age
    16 to 18
    Challenge level
    1 out of 3

    Explore the lattice and vector structure of this crystal.

  • Cross with the Scalar product
    problem

    Cross With the Scalar Product

    Age
    16 to 18
    Challenge level
    2 out of 3

    Explore the meaning of the scalar and vector cross products and see how the two are related.

  • Walls
    problem

    Walls

    Age
    16 to 18
    Challenge level
    3 out of 3

    Plane 1 contains points A, B and C and plane 2 contains points A and B. Find all the points on plane 2 such that the two planes are perpendicular.