FIGURE 11-6
-A 3.00-m-long ladder, weighing 200 N, rests against a smooth vertical wall with its base on a horizontal rough floor, a distance of 1.00 m away from the wall. If the center of mass of the ladder is 1.20 m from its base, what frictional force must the floor exert on the base of the ladder in order for the ladder to be in static equilibrium?
A) 93.3 N
B) 130 N
C) 28.3 N
D) 102 N
E) 150 N

Question

FIGURE 11-6 
-A 3.00-m-long ladder, weighing 200 N, rests against a smooth vertical wall with its base on a horizontal rough floor, a distance of 1.00 m away from the wall. If the center of mass of the ladder is 1.20 m from its base, what frictional force must the floor exert on the base of the ladder in order for the ladder to be in static equilibrium?
A) 93.3 N 
B) 130 N 
C) 28.3 N 
D) 102 N 
E) 150 N

Quizplus · Accepted Answer

The frictional force can be found using the torque equilibrium condition about the point where the ladder touches the floor. The torque due to the weight of the ladder must be balanced by the torque due to the normal force from the wall. Solving the equations gives a frictional force of 28.3 N.

FIGURE 11-6 -A 3.00-M-Long Ladder, Weighing 200 N, Rests Against a Smooth