Auniform metre rule of mass 200g is pivoted at 0cm mark. calculate the force which would be applied vertically up at the 60cm mark to keep the rule horizontal

Explanation:

There are two forces acting on the ruler: weight pulling down halfway at the 50cm mark, and the upward force at the 60cm mark.

Sum of the moments about the pivot:

∑τ = Iα

F (0.60) − (0.200) (9.8) (0.50) = 0

F = 1.63 N

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue