In addition to mobile home ad valorem taxes assessed and collected under authority of Chapter 53 of Title 27, Mississippi Code of 1972, the boards of supervisors are hereby authorized and empowered to levy a ten dollar ($10.00) ad valorem tax upon each mobile home or house trailer used as a family dwelling not heretofore occupied or used for residential purposes within the county as defined in Section 27-53-1, Mississippi Code of 1972, to be collected by the county tax assessor-collector annually and deposited into a county trust fund entitled "county school building and repair fund" and expended by the county board of education for capital improvements and equipment only in such compacted areas.