A balanced lever has two weights on it, the first with mass 8 kg 8kg and the second with mass 30 kg30kg. If the first weight is 7 m7m from the fulcrum, how far is the second weight from the fulcrum?

1 Answer
Dec 26, 2015

1.867m1.867m

Explanation:

I will apply the second condition of static equilibrium which states that the resultant torque (moments) must be zero,
ie. sum tau=0τ=0
where vectau=vecr xx vecFτ=r×F 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=0r1F1r2F2=0

therefore(7xx8g)-(r_2xx30g)=0

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

=1.867m.