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Solved: A 20.0-m-long uniform beam weighing 550 N rests on
Chapter 3, Problem 68GP(choose chapter or problem)
A 20.0-m-long uniform beam weighing \(550 \mathrm{~N}\) rests on walls \(\mathrm{A}\) and \(\mathrm{B}\), as shown in Fig. 9-80. (a) Find the maximum weight of a person who can walk to the extreme end D without tipping the beam. Find the forces that the walls \(\mathrm{A}\) and \(\mathrm{B}\) exert on the beam when the person is standing: (b) at D; (c) at a point \(2.0 \mathrm{~m}\) to the right of B; (d) \(2.0 \mathrm{~m}\) to the right of A.
Questions & Answers
QUESTION:
A 20.0-m-long uniform beam weighing \(550 \mathrm{~N}\) rests on walls \(\mathrm{A}\) and \(\mathrm{B}\), as shown in Fig. 9-80. (a) Find the maximum weight of a person who can walk to the extreme end D without tipping the beam. Find the forces that the walls \(\mathrm{A}\) and \(\mathrm{B}\) exert on the beam when the person is standing: (b) at D; (c) at a point \(2.0 \mathrm{~m}\) to the right of B; (d) \(2.0 \mathrm{~m}\) to the right of A.
ANSWER:
Step 1 of 4
Consider the extreme condition of the given beam. The beam will be ready to tip then there will no normal force 
The free body diagram of the beam can be shown as,
Apply the equilibrium condition, the moment about point B can be given as,
For 
Thus, the the maximum weight of a person who can walk to the extreme end D without tipping the beam is 