CREATE TABLE table_70806 ("Rank" FLOAT, "Fastest time  ( s ) " FLOAT, "Wind  ( m/s ) " FLOAT, "Athlete" TEXT, "Nation" TEXT, "Date" TEXT, "Location" TEXT)

what is the wind speed when brenda morehead was in the united states?
SELECT MIN("Wind (m/s)") FROM table_70806 WHERE "Nation" = 'united states' AND "Athlete" = 'brenda morehead'
SELECT MIN("Wind (m/s)") FROM "table_70806" WHERE "Athlete" = 'brenda morehead' AND "Nation" = 'united states'