Principle and Working:
Coplanar forces (weight, spring balance) act on the moments disc on either side of the pivot. In equilibrium, the moments are determined as a function of the magnitude and direction of the forces and of the reference point.
The spring balance is adjusted to zero in the position in which the measurement is to be made in each case. The straight line from the push-in button to the pivot point is adjusted to the horizontal by moving the swivel clamp on the stand rod. The fishing line to weight pan then runs along a row of holes. The spring balance should be mounted in the swivel clamp so that it forms an angle with the fishing line.
