A force of 18 N acts at right angles to a spanner, 0.25 m from the nut. What is the moment about the nut?
4.5 N m4.5\ \mathrm{N\,m}4.5 Nm
18.25 N m18.25\ \mathrm{N\,m}18.25 Nm
72 N m72\ \mathrm{N\,m}72 Nm
0.014 N m0.014\ \mathrm{N\,m}0.014 Nm