4-23. If d = 1 m, and 0 = 30°, determine the normal reaction at the smooth supports and the required distance a for the placement of the roller if P = 600 N. Neglect the weight of the bar. Prob. 4-23 4-23. If d = 1 m, and 0 = 30°, determine the normal reaction at the smooth supports and the required distance a for the placement of the roller if P = 600 N. Neglect the weight of the bar. Prob. 4-23