A uniform metre rule is balanced on a fulcrum placed at the 35cm mark by suspending a mass of 120g at the 10cm mark. Calculate the mass of the metre rule.
A
60g
B
80g
C
120g
D
200g
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Clock-wise moment = Anti-clock wise
Hence 120 \times (35−10)= Xg \times(50−35)
120 \times 25 = Xg \times 15
Xg = 200g
Source: Myschool Past Questions Archive (Record #45593)