Edexcel M5 2010 June — Question 4

Exam BoardEdexcel
ModuleM5 (Mechanics 5)
Year2010
SessionJune
TopicMoments

  1. Two forces \(\mathbf { F } _ { 1 } = ( \mathbf { i } + 2 \mathbf { j } + 3 \mathbf { k } ) \mathrm { N }\) and \(\mathbf { F } _ { 2 } = ( 3 \mathbf { i } + \mathbf { j } + 2 \mathbf { k } ) \mathrm { N }\) act on a rigid body.
The force \(\mathbf { F } _ { 1 }\) acts through the point with position vector ( \(2 \mathbf { i } + \mathbf { k }\) ) m and the force \(\mathbf { F } _ { 2 }\) acts through the point with position vector \(( \mathbf { j } + 2 \mathbf { k } ) \mathrm { m }\).
  1. If the two forces are equivalent to a single force \(\mathbf { R }\), find
    1. \(\mathbf { R }\),
    2. a vector equation of the line of action of \(\mathbf { R }\), in the form \(\mathbf { r } = \mathbf { a } + \lambda \mathbf { b }\).
  2. If the two forces are equivalent to a single force acting through the point with position vector \(( \mathbf { i } + 2 \mathbf { j } + \mathbf { k } ) \mathrm { m }\) together with a couple of moment \(\mathbf { G }\), find the magnitude of \(\mathbf { G }\).