Engineering Mechanics - Force System Resultants

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Exercise

General Questions

"Time and tide wait for none."

- Alexander Pope

36.

Express the moment of the couple acting on the pipe on Cartesian vector form. What is the magnitude of the couple moment?

A.	M_c = (37.5i-25j) N-m, M_c = 45.1 N-m
B.	M_c = (25i-37.5j) N-m, M_c = 45.1 N-m
C.	M_c =45.1kN-m, M_c = 45.1 N-m
D.	M_c =-45.1kN-m, M_c = 45.1 N-m

37.

Determine the direction (0° 180°) of the 30-lb force F so that the moment of F about point A has the maximum magnitude.

A.	= 36.9°
B.	= 53.1°
C.	= 127.0°
D.	= 90.0°

38.

Determine the moment of force F₂ about point A on the beam.

A.	M2 = 800 ft-lb
B.	M2 = 50 ft-lb
C.	M2 = 600 ft-lb
D.	M2 = 37.5 ft-lb

39.

The distributed loadings of soil pressure on the sides and bottom of a spread footing are shown. Simplify this system to a single resultant force and couple moment acting at A. What is the resultant force F and the couple moment M?

A.	F = (72i + 125j)N, M = 83.5 N-m CCW
B.	F = (144i + 125j)N, M = 135.7 N-m CCW
C.	F = (144i + 125j)N, M = 83.5 N-m CCW
D.	F = (72i + 125j)N, M = 102.1 N-m CCW

40.

Replace the two forces acting on the tree branches by an equivalent force and couple moment acting at point O.

A.	R = (60i+198j-36k) N, M = (747i+18j-924k) N-m
B.	R = (60i+18j-324k) N, M = (747i+18j-924k) N-m
C.	R = (60i+198j-36k) N, M = (360i+1260j-414k) N-m
D.	R = (60i+18j-324k) N, M = (360i+1260j-414k) N-m