Physics
A half metre rod is pivoted at the centre with two weights of 20 gf and 12 gf suspended at a perpendicular distance of 6 cm and 10 cm from the pivot respectively as shown below.
(i) Which of the two forces acting on the rigid rod causes clockwise moment?
(ii) Is the rod in equilibrium?
(iii) The direction of 20 gf force is reversed. What is the magnitude of the resultant moment of the forces on the rod?
Answer
(i) The force 12 gf rotates the rod clockwise.
(ii) Since, the clockwise moment (= 20 gf x 6 cm = 120 gf cm) is equal to the anticlockwise moment (= 12 gf x 10 cm = 120 gf cm), hence the rod is in equilibrium.
(iii) On reversing the direction of force, 20 gf will also produce clockwise moment, total clockwise moment will then be (20 gf x 6 cm + 12 gf x 10 cm) = 240 gf cm
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