Initially the balancing point is at center of the
meterstick.i.e., at 50 cm point
mass of the meter stick m = 0.12 kg
weight of the stick W = m g
                              Â
= 0.12*9.8 = 1.176 N
After suspended neckalce balancing point is moves 29 cmtoward that
end.
So, moment of force of stick = moment of force ofneckalce
                            Â
W* 29 = W ' * ( 50 -29 )
                       Â
1.176* 29 = 21 * W '
from this weight of the necklace  W '= 1.624 N
So, mass of the necklace m ' = W ' / g
                                          Â
= 0.1657 kg
                                          Â
= 165.7 g
