Balance of bank account.

Place of fulcrum is important for balance. Most people think, fulcrum of balance in bank account means 0 deposit 0 loan, and cannot move it. But actually, rich people has big amount of loan, and they regard that is balanced as same as the 0 deposit 0 loan.

Condition of leverage of balance is defined by length between each point.
Set premise: when moving goods with money, place of goods on the market cannot move randomly, so point of load is fixed.

The weight is kind of currency. Condition of lever is defined by point of fulcrum and effort.
The point of fulcrum is account owner feels 0 deposit 0 loan point. The point of effort is how much currency you have.
 In practice, power to move fulcrum is credit information from loan company.