If the screen width is 7 feet and the projector's throw ratio is 2.0 - 2.4:1 (because projectors have zoom lenses, they also have a range of throw ratios) then you can place your projector anywhere from 14 to 16.8 feet away from the screen.
A strain gauge (or strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern.he gauge is far more sensitive to strain in the vertical direction than in the horizontal direction.
Tensile stress results in the elongation of the member. If the original length is (l) and the change in the length is , strain () is defined as: Therefore, stress represents the applied force and strain represents the resulting deformation.