A light beam is pivoted at its centre. Downward forces of 20 N and 30 N act 0.40 m to the left and 0.20 m to the right respectively. An additional force acts 0.50 m to the right. Which additional force balances the beam?
4.0 N4.0\ \mathrm{N}4.0 N downwards.
4.0 N4.0\ \mathrm{N}4.0 N upwards.
28 N28\ \mathrm{N}28 N upwards.
28 N28\ \mathrm{N}28 N downwards.
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.