The following formula is used to calculate the specific gravity of a material. Where SG = specific gravity, Ï = density of the material (kg/m3), ÏW = density of water ( kg/m3). The reference density of water at 4oC (39oF) is used as the reference as these are the conditions of maximum density.
Most business owners donât know how long they should hold on to old records. According to the IRS, hereâs how long you should keep those records: Permanently: 1  general ledgers and journals. 2  payroll records, including W-2s, 940s, 941s. 3  year-end financial statements.4  tax returns and supporting documents. 5  articles of incorporation, bylaws, meeting minutes, etc. 6  retirement plan records.ost business owners donât know how long they should hold on to old records. According to the IRS, hereâs how long you should keep those records: Permanently: 1  general ledgers and journals. 2  payroll records, including W-2s, 940s, 941s. 3  year-end financial statements. 4  tax returns and supporting documents.
As a rule, records and supporting documents must be kept for at least six years after the taxation year to which they pertain. It may be necessary for you to keep your records for more than six years if you file your return late, you file a notice of objection or you file an appeal with the courts.