A uniform girder AB AB\,AB has length 11 m and mass 18 kg. It is supported horizontally by a single pivot at PPP, where AP=4AP=4AP=4 m. A ballast weight of magnitude W W\,W N is attached at end A A\,A so that the girder is in equilibrium.
Determine WWW. Use g=9.8g=9.8g=9.8 m s−2^{-2}−2.
State how the assumption that the girder is uniform has been used.