A balanced lever has two weights on it, the first with mass 8 kg and the second with mass 3 kg. If the first weight is 2 m from the fulcrum, how far is the second weight from the fulcrum?

1 Answer
Jan 11, 2016

5.333m

Explanation:

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

So application in this case yields :

r_1F_1-r_2F_2=0

therefore (2xx8g)-(r_2xx3g)=0

therefore r_2=(2xx8xx9.8)/(3xx9.8)=5.333m.