A balanced lever has two weights on it, the first with mass #6 kg # and the second with mass #7 kg#. If the first weight is # 4 m# from the fulcrum, how far is the second weight from the fulcrum?
As we are determining the distance it does not matter what units of weight we use as long as they are consistent.
I am also going to demonstrate how to deal with the units of measurement. If you deal with 'Statics' to any extent then manipulating units is exceptionally important!
If the moments do not match then it means that the system is in motion. We can use this fact to determine the moment arms needed to establish equilibrium.
A Moment is the number resulting from an applied force multiplied by its distance to a point of rotation ( actual or theoretical).
Let clockwise moment be positive.
Let anticlockwise moments be negative
Then for equilibrium to exist
For this to be true then: