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. Stone S1 S_1\,S1 is thrown from C C\,C with speed 20 ms-1 at an angle of 60∘ 60^\circ\,60∘ to the horizontal. Stone S2 S_2\,S2 is thrown from D D\,D with speed U ms−1U \text{ ms}^{-1}U ms−1 at an angle of θ \theta\,θ to 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.
91 exam-style questions on OCR (MEI) A Level Maths 3.3 Projectiles (A-level only), covering 3.3.1 Model motion under gravity using vectors (A-level only), 3.3.2 Position, velocity, range and maximum height (A-level only), 3.3.3 Find the initial velocity of a projectile (A-level only), 3.3.4 Equation of the trajectory (A-level only), and 3.3.5 Solve simple projectile problems (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.