BackA uniform beam of length and mass rests horizontally on two supports, one at each end. If a downward point load is applied at a distance from the left end, which of the following expressions gives the reaction force at the left support?
A board 8 m in length, 20 kg in mass, and of uniform mass distribution, is supported by two scales placed underneath it. The left scale is placed 2 m from the left end of the board, and the right scale is placed on the board's right end. A small object 10 kg in mass is placed on the left end of the board. Calculate the reading on the left scale. (Use g=10 m/s2.)
BONUS:Calculate the reading on the right scale.
The roof over a 9.0-m x 10.0-m room in a school has a total mass of 12,400 kg. The roof is to be supported by vertical wooden “2 x 4s” (2 x4 in inches, but actually about 4.0 x 9.0 cm) equally spaced along the 10.0-m sides. How many supports are required on each side, and how far apart must they be? Consider only compression, and assume a safety factor of 12.
A heavy load Mg = 62.0 kN hangs at point E of the single cantilever truss shown in Fig. 12–81. Use a torque equation for the truss as a whole to determine the tension FT in the support cable, and then determine the force on the truss at pin A. Neglect the weight of the trusses, which is small compared to the load.
A 350-N, uniform, 1.50-m bar is suspended horizontally by two vertical cables at each end. Cable A can support a maximum tension of 500.0 N without breaking, and cable B can support up to 400.0 N. You want to place a small weight on this bar. (a) What is the heaviest weight you can put on without breaking either cable, and (b) where should you put this weight?