A new physics teacher and principal are hired at an East Texas high school, less than a month after a student was maimed in a physics project explosion. Last night, the Winona School Board hired Robert Lock to replace Bradley Brown as physics teacher. Brown resigned after a cannon explosion injured 17-year-old Johnathon Strength. Former Warren ISD Administrator Leland Hand has been brought in as principal, replacing former principal Brent Rumbo. He also resigned after the explosion. The ATF is expected to complete its investigation of the explosion in a few weeks.