Three different forces are shown pulling on a heavy trapdoor. Which force will have the biggest turning effect$?$ Explain your answer.

Calculate the unknown forces $X$ and $Y$ for the balanced beam shown.

The been shown is balanced at its midpoint. The weight of the beam is $40\mathrm{N}$. Calculate the unknown force $Z$, and the length of the beam.

Use the ideas of stability and centre of mass to explain the following.

Double-backer buses have heavy weights attached to their undersides.

Use the ideas of stability and centre of mass to explain the following.

The crane has a heavy concrete block attached to one end of its arm, and others placed around its base.