A tennis ball is projected with speed U ms−1U \text{ ms}^{-1}U ms−1 from a point OOO, which is 1.5 m above the horizontal ground. The ball is projected at an angle α∘ \alpha^\circ\,α∘ to the horizontal. During its flight, the ball reaches a maximum height of 4.5 m above the ground and passes through a point AAA, which is 0.5 m above the ground and at a horizontal distance of 12 m from OOO. The ball is modeled as a particle moving under gravity.
Find the value of UUU.
Find the size of angle α\alphaα.
State one limitation of the model that could affect the accuracy of your answers.
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.