Three forces act on a particle of mass 4 kg. The forces are (5i+2j)(5\mathbf{i} + 2\mathbf{j})(5i+2j) N, (−3i+7j)(-3\mathbf{i} + 7\mathbf{j})(−3i+7j) N and (2i−4j)(2\mathbf{i} - 4\mathbf{j})(2i−4j) N, where i\mathbf{i}i and j\mathbf{j}j are perpendicular unit vectors in a horizontal plane.
Find the resultant of the three forces.
Find the magnitude of the acceleration of the particle.
Find the angle between the acceleration and the direction of i\mathbf{i}i.
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.