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**Problem: A 40kg, 5.0m long beam is supported by, but not attached to, the two posts in the figure. A 20kg boy starts walking along the beam. How close can he get to the right end of the beam without it falling over?**

http://student.ucr.edu/~meliz003/phy.JPG [Broken]

*My answer:*

\tau_net = (F_1*x_F_1)-(F_Beam*X_Beam)-(F_Boy*X_Boy)

Since, \tau_net = 0

0 = (F_1*x_F_1)-(F_Beam*X_Beam)-(F_Boy*X_Boy)

0 = (40*3)-(40*2)-(20*X_boy)

Comes out to X_Boy = 2?

So the boy has to step at the very edge of the beam for it to start falling over?

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