A uniform steel girder ABABAB of length 999 metres is held in a horizontal position by two smooth supports at CCC and DDD. The support at CCC is 1.51.51.5 metres from end AAA, and the support at DDD is 333 metres from end BBB.
The upward reaction force exerted on the girder by the support at CCC is 6g6g6g newtons.
(i) Show that the mass of the girder is 181818 kilograms.
(ii) Find the magnitude of the reaction force at support DDD, leaving your answer in terms of ggg.
The support at DDD is shifted such that the distance BD=1.5BD = 1.5BD=1.5 metres, while the girder remains in horizontal equilibrium. A technician claims that the reaction force at DDD will remain equal to the value found in part (a)(ii). Explain, with a reason, whether this claim is correct.
130 exam-style questions on Edexcel A Level Maths Applications of Forces, covering 7.1 Static Particles, 7.2 Modelling with Statics, 7.3 Friction and Static Particles, 7.4 Static Rigid Bodies, 7.5 Dynamics and Inclined Planes, and 7.6 Connected Particles 2. Each one has a worked solution and a mark scheme showing where the marks go.