A uniform horizontal beam AB AB\,AB of length 8.0 m and mass 15 kg is supported in equilibrium by two pivots: one located at the end A A\,A and another at point DDD, which is 5.0 m from AAA. A mass of 3.0 kg is suspended from the free end BBB, as shown in the diagram.
Using g=9.8 m s−2g = 9.8\text{ m s}^{-2}g=9.8 m s−2, calculate the magnitude of the normal reaction force exerted on the beam by the pivot at DDD.
11.8 N11.8\text{ N}11.8 N
47.0 N47.0\text{ N}47.0 N
165 N165\text{ N}165 N
274 N274\text{ N}274 N