According to the law of moments, how is balance achieved in a lever?

Balance in a lever is achieved according to the law of moments through the relationship between the weights on either side of the fulcrum and their respective distances from that fulcrum. Specifically, when an object is balanced on a lever, the moments or torques created by the weights must be equal on both sides of the fulcrum. The moment is calculated by multiplying the weight of an object (force due to gravity) by its distance from the fulcrum, known as the lever arm. When this multiplication results in equal values on both sides, the lever remains in balance.

For instance, if you have a weight of 5 kg placed 2 meters from the fulcrum on one side, you would need a weight of 2.5 kg placed 4 meters from the fulcrum on the other side to achieve balance, since both moments would equal 10 kg·m.

The other choices do not accurately depict the principle governing balance in a lever system. The requirement for the effort force to equal the resistance force does not consider the distances involved. Placing the fulcrum in the center may not result in balance if the weights are not also appropriately distributed. Lastly, minimizing torque does not adhere to the balance principle