$\begin{aligned} & \overrightarrow{\mathrm{F}}=(4 \hat{\mathrm{i}}-10 \hat{\mathrm{j}}) \mathrm{N} \\ & \overrightarrow{\mathrm{r}}=(-5 \hat{\mathrm{i}}-3 \hat{\mathrm{j}}) \mathrm{m} \\ & \overrightarrow{\mathrm{r}} \times \overrightarrow{\mathrm{F}}=\left|\begin{array}{ccc}\hat{\mathrm{i}} & \hat{\mathrm{j}} & \hat{\mathrm{k}} \\ -5 & -3 & 0 \\ 4 & -10 & 0\end{array}\right| \\ & =\hat{\mathrm{k}}(50+12)=62 \hat{\mathrm{k}} \mathrm{Nm}\end{aligned}$