At time t t\,t seconds, where t≥0t \ge 0t≥0, a particle P P\,P has position vector r=[(t2−4t)i+3tj]\mathbf{r} = \left[(t^2 - 4t)\mathbf{i} + 3t\mathbf{j}\right]r=[(t2−4t)i+3tj] m.
Find the values of t t\,t at which the speed of P P\,P is 5 m s−1^{-1}−1.
260 exam-style questions on OCR A Level Maths 3.2 Kinematics, covering 3.2.1 Language of kinematics, 3.2.2 Graphs in kinematics, 3.2.3 Displacement-time and velocity-time graphs, 3.2.4 Constant acceleration formulae, 3.2.5 Constant acceleration in two dimensions (A-level only), 3.2.6 Non-uniform acceleration in one dimension (A-level only), 3.2.7 Non-uniform acceleration in two dimensions (A-level only), 3.2.8 Motion under gravity using vectors (A-level only), and 3.2.9 Projectiles (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.