Problom $2$

A safety engineer establishing limits on the load that can be carried by a forklift analyzes the situation shown. The dimensions are $a=1\mathrm{.}10m,b=0\mathrm{.}75m$ and $c=0\mathrm{.}6m.$ The combined weight of the forklift and operator is $W_i=4\mathrm{.}5kN.$ As the weight $W_L$ supported by the forklift increases, the normal force exerted on the floor by the rear wheels at $B$ decreases. The forklift is on the verge of tipping forward when the normal force at $B$ is zero. Determine the value of $W_L$ that will cause this condition $($overturning$).$