Question

Calculate the moment about a point C caused by the forces acting at the points A&B respectively (engineering)?

Can somebody please help me with these 2 problems? Thanks so much!!

Calculate the moment about a point CC – 4, 5, 7) ft caused by the forces F1 = – 4i + 4% – 8k lb and F, = – 3i – 7j + 7k lb acting at the points AC – 2, – 4, – 1) ft and B(2, 2, 6) ft, respectively. Mc = ( i + j+ k) lb. ft

Answer 1

Moment ec due to fi = VCA XE I A -C] xf [ 28 -9 ; -84 X(-41 +4 Cross +4j*–84" cross Product 1 j 2 -4 -9 4 - 8 - 104 ľ + 487 - 28% eb. ft Mer due to F2 = 8cB X F2 = [61-3jn - Ik x [-31 - 7j + 76 -28 1 - 39 j - 51k eb, ft ". Me e due to F 4 F2 {j tek = 761 +89; -79 kr 76i +9 79 k' 16. ft A Ein + E Answer

F = F. UBA Arrow head of F is from B to A. 21 = 21 JABI Nine tgk ✓ 82 loi A = -1.5566 15.5662; + 14.0096k ab Meo due to f =VOA XF = [ 6e - 5j + 12K"] , 116.7464 102.7368 - 101 1802k 16. ft Answer Mec due to F NCA X F I Ã] x =[12 f = 12 + 5*] x = -90.284279 175.8982 ; - 205.4736 XF k eb.it Answer