horizontal bar

Problem 532
In Fig. P-532, two blocks each weighing 1.5 kN are connected by a uniform horizontal bar which weighs 1.0 kN. If the angle of friction is 15° under each block, find P directed parallel to the 45° incline that will cause impending motion to the left.
 

Problem 530
A plank 10 ft long is placed in a horizontal position with its ends resting on two inclined planes, as shown in Fig. P-530. The angle of friction is 20°. Determine how close the load P can be placed to each end before slipping impends.