7 A rectangular book ABCD rests on a smooth horizontal table. The length of AB is 28 cm and the length of AD is 18 cm . The following five forces act on the book, as shown in the diagram.
- 4 N at A in the direction AD
- 5 N at B in the direction BC
- 3 N at B in the direction BA
- 9 N at D in the direction DA
- 3 N at D in the direction DC
\includegraphics[max width=\textwidth, alt={}, center]{1d0ca3d5-6529-435f-a0b8-50ea4859adde-06_663_830_774_242}
- Show that the resultant of the forces acting on the book has zero magnitude.
- Find the total moment of the forces about the centre of the book. Give your answer in Nm .
- Describe how the book will move under the action of these forces.