Question

A half metre rod is pivoted at the center with two weight of 20gf and 12gf suspended at a perpendicular distance of 6cm and 10cm from the pivot respectively. . (I) wch of the following two force acting on the rigid rod causes clockwise moment? (II) is the rod in equilibrium? (III) the direction of 20gf force is reversed. what is the magnitude of the resultant moment of the forces on the rod?

Answer 1

(i)12gf acting on the rigid rod causes clockwise moment

.(ii)Yes, the rod is in equilibrium because  both clockwise  and anti-clockwise moments are the same. ( F1 x S1 = F2 x S2 )

(iii)If 20 gf is reversed,both forces give clockwise moment. Total clockwise moment is 2×120×9.8×10−3 N-m =2.352 N-m