Two drones, A A\,A and BBB, are performing a synchronized maneuver with constant velocity vectors. The velocity of drone A A\,A is vA=(15i−25j+10k) m s−1\mathbf{v}_A = (15\mathbf{i} - 25\mathbf{j} + 10\mathbf{k}) \text{ m s}^{-1}vA=(15i−25j+10k) m s−1 and the velocity of drone B B\,B is vB=(ki+10j−4k) m s−1\mathbf{v}_B = (k\mathbf{i} + 10\mathbf{j} - 4\mathbf{k}) \text{ m s}^{-1}vB=(ki+10j−4k) m s−1, where k k\,k is a constant. Given that the direction of motion of drone B B\,B is parallel to the direction of motion of drone AAA, determine the value of kkk.
168 exam-style questions on OCR (MEI) A Level Maths 1.11 Vectors, covering 1.11.1 Language of vectors in two dimensions, 1.11.2 Add, subtract and scale vectors, 1.11.3 Magnitude and direction of a vector, 1.11.4 Position vectors, 1.11.5 Distance between points by position vectors, 1.11.6 Vectors to solve problems, 1.11.7 Language of vectors in three dimensions (A-level only), and 1.11 Vectors. Each one has a worked solution and a mark scheme showing where the marks go.