Ejercicio 4.5 Un soporte en forma de T sostiene las cuatro cargas mostradas. Determínense las reacciones en A y B si a) a = 10 in y b) a = 7 in.

∑ MA = (-12 i in x Ay j) + (-6 i in x –40 j lb) + (10 i in x –30 j lb) +

(18 i in x –10 j lb) -12 k in Ay + 240 k lb in –300 k lb in – 180 k lb in = 0 -12 k in Ay – 240 k lb in = 0 Ay = 240 k lb in = 20 lb 12 k in ∑ MA = (-12 i in x Ay j) + (-6 i in x – 40 j lb) + (7 i in x –30 j lb) +

(15 i in x –10 j lb) -12 k in Ay + 240 k lb in –210 k lb in – 150 k lb in = 0 -12 k in Ay – 120 k lb in = 0 Ay = 120 k lb in = 10 lb 12 k in ∑ Fy = 20 lb – 40 lb – By lb – 50 lb – 30 lb – 10 lb = 0 By = 110 lb ∑ Fy = 10 lb – 40 lb – By lb – 50 lb – 30 lb – 10 lb = 0 By = 120 lb ∑ Fx = 0