A precision-controlled submersible of mass m m\,m is being tested in a deep-water tank. It moves under the influence of two horizontal forces, F1\mathbf{F}_1F1 and F2\mathbf{F}_2F2.
It is given that
F1=(2.5i−14.8j) N \mathbf{F}_1 = (2.5\mathbf{i} - 14.8\mathbf{j}) \text{ N} F1=(2.5i−14.8j) N F2=(0.4ki+1.2kj) N \mathbf{F}_2 = (0.4k\mathbf{i} + 1.2k\mathbf{j}) \text{ N} F2=(0.4ki+1.2kj) Nwhere k k\,k is a constant.
The submersible experiences an acceleration of (1.5i+2j) m s−2(1.5\mathbf{i} + 2\mathbf{j}) \text{ m s}^{-2}(1.5i+2j) m s−2.
Determine the value of kkk.
139 exam-style questions on AQA A Level Maths 3.3 R: Forces and Newton's laws, covering 3.3.1 Concept of a force and Newton's first law, 3.3.2 Newton's second law, 3.3.3 Weight and motion under gravity, 3.3.4 Newton's third law and equilibrium, 3.3.5 Addition of forces and resultants (A-level only), and 3.3.6 Friction (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.