Two stones, S1 S_1\,S1 and S2S_2S2, are thrown simultaneously from points C C\,C and D D\,D which are 80 m apart on horizontal ground. Assume C C\,C is to the left of DDD. Stone S1 S_1\,S1 is thrown from C C\,C towards D D\,D with speed 20 ms-1 at an angle of 60∘ 60^\circ\,60∘ above the horizontal. Stone S2 S_2\,S2 is thrown from D D\,D towards C C\,C with speed U ms−1U \text{ ms}^{-1}U ms−1 at an angle of θ \theta\,θ above the horizontal. The stones collide 2 seconds after being thrown. Gravity is the only force acting on the stones once they are in the air.
Find the velocity of S1 S_1\,S1 the instant before it collides with S2S_2S2.
Find the size of angle θ\thetaθ.
Find the value of UUU.
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.