9-18. A simply supported beam is subjected to a quadratic distributed load as shown in Fig. P9.18. y Figure P9.18 Simply supported beam subjected to a quadratic distributed load. a. Determine the total resultant force, w(x) = - Wo x(x-21) R= = So w w(x) dx. b. Determine the x-location of the resultant R; in other words, determine the centroid of the area under the distributed load fox w(x) dx x = R Wo X