Question

A metre scale is pivoted from the 0 cm mark and is free to rotate in the vertical plane. A 50 g weight is suspended from the 20 cm mark as shown in the figure. Calculate the moment of force in gf × cm and in N m.

Answer 1

Given Data:

Force (F) = 50 gf

Pivot position = 0 cm mark

Position of weight = 20 cm mark

Perpendicular distance (d) = 20 − 0 = 20 cm

1. Calculation in gf . cm:

Moment of Force = Force (F) × Distance (d)

= 50 gf × 20 cm

= 1000 gf . cm

2. Calculation in N . m:

Convert Force to Newtons = 50 gf = `50/1000` kgf = 0.05 kgf = 0.05 × 9.8 N = 0.49 N

Convert Distance to Meters = 20 cm = `20/100` m = 0.2 m

Moment of Force = 0.49 N × 0.2 m

= 0.098 N . m