Figure $5$

f$)$ There has been an explosion at the FOC$4005$ Headquarters. Forensic Fire and Explosion Investigators went to process the scene of the explosion. The seat of the explosion was located, and the dimensions of the crater were $\backslash ($ a$=1\mathrm{.}5\backslash$mathrm$\{$~m$\}\backslash )$ and $\backslash (\backslash$mathbf$\{$h$\}=0\mathrm{.}75\backslash$mathrm$\{$~m$\}\backslash ).$ The lead investigator P $.$ Wint, proposed that because the crater is nearly circular, the crater's approximate volume can be calculated by using the formula for the volume of a spherical cup $($i$.$e$.,$ crater$)\backslash ($ V$=\backslash$pi h $/6\backslash$left$(3$ a$^\{2\}+$h$^\{2\}\backslash$right$)\backslash ).$

Determine the approximate charge weight W of the explosive material.