Aunifrom pole of mass 20kg and length 6m is supported horizontally at its ends by two knife edges A and B. A mass of 120kg is now suspended at a distance 2m from A. Calculate reaction forces at the knife edges.

Aunifrom pole of mass 20kg and length 6m is supported horizontally at

1.	Aunifrom pole of mass 20kg and length 6m is supported horizontally at its ends by two knife edges A and B. A mass of 120kg is now suspended at a distance 2m from A. Calculate reaction forces at the knife edges.
Answer» Solution : GIVEN W=20 kg wt, P=120 kgwt, AC=BC=3m, AD=2m For STATIC equilibrium sum of UPWARD forces = sum of downward forces `R_1+R_2=120+20=140kg wt` TAKING moments about B, we write `20bar(BC)+120bar(BD)=R_1bar(BA)`, Moment of `R_2` about `B=O` `20xx3+120(4)=R_1(6)` `R_1=(540)/6=90kg wt` and `R_2=140-90=50kg wt`