A light ventilation flap is held stationary about a pivot. One actuator produces a clockwise moment of 5.4 N m, while another produces an anticlockwise moment of 2.1 N m. A spring provides the remaining anticlockwise moment by exerting a force with a perpendicular distance of 0.60 m from the pivot. What is the force exerted by the spring?
3.5 N3.5\ \mathrm{N}3.5 N
12.5 N12.5\ \mathrm{N}12.5 N
5.5 N5.5\ \mathrm{N}5.5 N
2.0 N2.0\ \mathrm{N}2.0 N
102 exam-style questions on Edexcel GCSE Physics 9.2 Moments, covering 9.2.1 Rotational effects of forces and moments, 9.2.2 The principle of moments, and 9.2.3 Levers and gears. Each one has a worked solution and a mark scheme showing where the marks go.