Which row in the table below correctly shows the conditions required for a rigid body to be in mechanical equilibrium?
Net external force, ∑FNet external moment, ∑MA∑F=0∑M=0B∑F=0∑M≠0C∑F≠0∑M=0D∑F≠0∑M≠0 \begin{array}{|c|c|c|} \hline & \text{Net external force, } \sum \mathbf{F} & \text{Net external moment, } \sum \mathbf{M} \\ \hline \text{A} & \sum \mathbf{F} = 0 & \sum \mathbf{M} = 0 \\ \hline \text{B} & \sum \mathbf{F} = 0 & \sum \mathbf{M} \neq 0 \\ \hline \text{C} & \sum \mathbf{F} \neq 0 & \sum \mathbf{M} = 0 \\ \hline \text{D} & \sum \mathbf{F} \neq 0 & \sum \mathbf{M} \neq 0 \\ \hline \end{array} ABCDNet external force, ∑F∑F=0∑F=0∑F=0∑F=0Net external moment, ∑M∑M=0∑M=0∑M=0∑M=0Row A
Row B
Row C
Row D
245 exam-style questions on CIE IGCSE Physics 1.5 Forces, covering 1.5.1a Forces, resultant force and motion, 1.5.1b Load–extension graphs and the spring constant, 1.5.1c Friction and drag, 1.5.1d Force, mass and acceleration, 1.5.1e Motion in a circular path, 1.5.2a Moment of a force, 1.5.2b Principle of moments and equilibrium, and 1.5.3 Centre of gravity and stability. Each one has a worked solution and a mark scheme showing where the marks go.