Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

« Exit Print View Print The Method of Sections Learning Goal: To apply the metho

ID: 1843917 • Letter: #

Question

« Exit Print View

Print

The Method of Sections

Learning Goal:

To apply the method of sections to a truss and determine the unknown forces in specified members.

If a truss is in equilibrium then every member in the truss must also be in equilibrium. This principle is used in analyzing a truss using the method of sections. To apply the method of sections, we use an imaginary cut through members of the truss to expose the forces in those members as external forces.

If the free-body diagram of the joint on either side of the cut is known, we can apply the equations of equilibrium to that part of the member to determine the forces at the cut section. Since only three equilibrium equations (Fx=0, Fy=0, and MO=0) can be applied to the free-body diagram of any segment, we should try to select a cut that passes through no more than three members of the truss in which the forces are unknown.

For the Howe bridge truss shown, d=11 ft,F1=3050 lb, F2=1850 lb, F3=2350 lb, and F4=3850 lb.

Part A - Determining the forces in three members on the right-hand side of the truss

Determine the forces in members HD, CD, and GD.

Express the magnitudes of the forces in pounds to three significant figures. Separate your answers with commas.

You did not open hints for this part.

ANSWER:

Part B - The Sense of the Forces

State if the members considered in part A are in tension or compression.

Complete each sentence by dragging the appropriate word into the blank. The words can be used more than once.

ANSWER:

Help

Reset

compression

tension

Member DH is in .

Member CD is in .

Member DG is in .

Part C - Determining the forces in three members on the left-hand side of the truss

Determine the forces in members HI, BH, and BC.

Express the magnitudes of the forces in pounds to three significant figures. Separate your answers with commas.

You did not open hints for this part.

ANSWER:

Part D - The Sense of the Forces

State if the members considered in part C are in tension or compression.

Complete each sentence by dragging the appropriate word into the blank. The words can be used more than once.

ANSWER:

Help

Reset

compression

tension

Member BC is in .

Member HI is in .

Member BH is in .

FDH=, FCD=, FDG= lb, lb, lb nternal AT tensile Tension YT Internal C compressive forces Compression C

Explanation / Answer

FDH = 6928.6 lb (COMPRESSION)

FCD = 4900 lb (TENSION)

FGD = 4900 lb (TENSION)

FBC = 1850 lb (TENSION)

FHI = 3050 lb (COMPRESSION)

FBH = 6928.6 lb (COMPRESSION)