A balanced lever has two weights on it, the first with mass #8 kg # and the second with mass #30 kg#. If the first weight is # 7 m# from the fulcrum, how far is the second weight from the fulcrum?

1 Answer
Dec 26, 2015

Answer:

#1.867m#

Explanation:

I will apply the second condition of static equilibrium which states that the resultant torque (moments) must be zero,
ie. #sum tau=0#
where #vectau=vecr xx vecF# is the algebraic cross product of the position vector from the axis of rotation (fulcrum) to the applied force, and the applied force.

So in this particular case,

#r_1F_1-r_2F_2=0#

#therefore(7xx8g)-(r_2xx30g)=0#

#thereforer_2=(7xx8xx9,8)/(30xx9,8)#

#=1.867m#.