A .jack stand for supporting an automobile or truck during servicing is shown. The stand h...

A .jack stand for supporting an automobile or truck during servicing is shown. The stand has three legs with equal radial positioning. The height h of the stand can be adjusted between 9 and 15 in. If the stand supports a 15001b vertical force, determine the smallest horizontal force F that will cause the moment about line .AB to be zero and hence cause the stand to tip.

Figure P4.84