OCR MEI M1 — Question 2

Exam BoardOCR MEI
ModuleM1 (Mechanics 1)
TopicNon-constant acceleration

2 The position vector of a particle at time \(t\) is given by $$\mathbf { r } = \frac { 1 } { 2 } t \mathbf { i } + \left( t ^ { 2 } - 1 \right) \mathbf { j } .$$ referred to an origin \(O\) where \(\mathbf { i }\) and \(\mathbf { j }\) are the standard unit vectors in the directions of the cartesian axes Ox and Oy respectively.
  1. Write down the value of \(t\) for which the \(x\)-coordinate of the position of the particle is 2 . Find the \(y\)-coordinate at this time.
  2. Show that the cartesian equation of the path of the particle is \(y = 4 x ^ { 2 } - 1\).
  3. Find the coordinates of the point where the particle is moving at \(45 ^ { \circ }\) to both Ox and Oy .