Chapter 11, Problem 11.5E

Raising a Ladder. A ladder carried by a fire truck is 20.0 m long. The ladder weighs 3400 N and its center of gravity is at its center. The ladder is pivoted at one end (A) about a pin (Fig. E11.5); ignore the friction torque at the pin. The ladder is raised into position by a force applied by a hydraulic piston at C. Point C is 8.0 m from A, and the force $\stackrel{\to }{F}$ exerted by the piston makes an angle of 40° with the ladder. What magnitude must $\stackrel{\to }{F}$ have to just lift the ladder off the support bracket at B? Start with a free-body diagram of the ladder.

Figure E11.5