Answer:
40 gram or 0.04 kilogram
Explanation:
From the diagram attached,
The mass must be suspended at end B.
Applying the principle of moment,
Sum of clockwise moment = sum of anti-clockwise moment.
From the diagram,
Taking the moment about the pivot,
X(60-50) = 0.1(100-60)
Where X = weigth of the meter rule
10X = 4
X = 4/10
X = 0.4 N
X = 0.4/10
X = 0.04 kg
X = 40 g
Hence the mass of the meter rule = 0.04 kg or 40 gram