Question

Two forces each of 5N act vertically upwards and downwards respectively on the two ends of a uniform metre rule which is placed at its mid-point as shown in the diagram. Determine the magnitude of the resultant moment of these forces about the midpoint.

Answer 1

Moment of force F1 = 5 ⨯ 25 = 125
Moment of force F2 = 5 ⨯ 25 = 125
Since both the forces are acting in anticlockwise direction, the resultant moment of force is the sum of the two moments.
∴ Resultant moment of force = 125 + 125 = 250

Answer 2

M = `"F" × vec("d")` (or) F × S

M = `5xx50/100 "m"`

= 5 × 0.5

= 2.5 Nm.