Question

A uniform metre rule is ab is pivoted 30cm from end a. It balances horizontally when a weight of 5n is hug at a.calculate the weight of the metre rule.

Answer 1

center of meter rule weight w at 50 cm
5 N at 0
(5+w) up at 30
moments about a (zero end)
30 (5+w) = 50 w
150 + 30 w = 50 w
20 w = 150
w = 7.5 Newtons