In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A particle is projected from a point O O\,O on horizontal ground with speed 21 m s−1^{-1}−1 at an angle θ \theta\,θ above the horizontal. Air resistance is modelled as negligible.
The particle passes through the point which is 20 m horizontally and 5 m vertically from OOO.
By writing down expressions for the horizontal and vertical displacements of the particle in terms of t t\,t and eliminating ttt, find the two possible values of θ\thetaθ.
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.