Q$(1)$: Direct shear tests wiere performed on a sandy soil. The size of sulecimen was $2$ in$.2$ in$.0\mathrm{.}75$ in$.$ the test results were as follows:

$\backslash$table$[[$Test No$.,$Normal force $(1$b$),$Shear force $($Ib$)],[1,20,12\mathrm{.}0],[2,30,18\mathrm{.}3],[3,70,42\mathrm{.}1],[4,100,60\mathrm{.}1]]$