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Assignment in the Analysis of Trusses

Assignment - S.M.2,Unit-6
1.Find the internal forces in member AB,AC,BC by using Method of Joints.

2.Find the internal forces in all members of a pin jointed truss by using Method of Joints. P= 12kN

3.Find the internal forces in all members of a pin jointed truss by using Method of Joints.

4.Find the internal forces in BD, CD and CE members of a pin jointed truss by using Method of sections.
5.Find the internal forces in GF,GC,FC members of a pin jointed truss by using Method of sections.

Objective questions and answers 

1. How many equilibrium equations do we need to solve generally on each joint of a truss?
     a) 1    b) 2      c) 3       d) 4
2. If a member of a truss is in compression, then what will be the direction of force that it will apply to the joints?
   a) Outward     b) Inward     c) Depends on case 
   d) No force will be there
3.What should be ideally the first step to approach to a problem using method of joints?
   a) Draw fbd of each joint      b) Draw fbd of overall truss
   c) Identify zero force members 
   d) Determine external reaction forces
Answer: c
Explanation: Identifying zero force members should always be the first step to approach any truss problem as it eliminate a lot of variables and is fairly easy.
4. The free body diagram of which part of the section of the truss is made to make use of method of joints?
  a) Joints     b) Truss        c) The whole structure 
  d) The combination of joint and whole structure
5. For applying the method of joint at joints the forces need to coplanar.
  a) False     b) True
Answer: b
Explanation: The forces are coplanar that’s why they are there in the calculations in the method of joints. The forces are resolved in 2D. This makes the condition of the equilibrium fulfilled and hence the method of joints uses the forces in the same plane for its calculation.
6. For applying the method of joint at joints the forces need to be concurrent.
    a) False         b) True
Answer: b
Explanation: The forces are concurrent that’s why they are there in the calculations in the method of joints. The forces are resolved in 2D. This makes the condition of the equilibrium fulfilled by cancelling of various force members and hence the method of joints uses the concurrent forces for its calculation.
7. What is after taking the assumption of the direction of the force, the direction comes opposite?
a) The assumption made was wrong and the question can’t be solved further
b) The assumptions are not to be taken
c) The direction is in the opposite sense, and hence the direction is known to us
d) The direction will be already given to us, no need of assuming
Answer: c
Explanation: The direction is comes opposite, means that the assumption was wrong. But that doesn’t means that the question can’t be solved further. One needs to change the sign of the direction and the question is solved. Thus the calculations of the force direction.
8. If the whole truss is in equilibrium then all the joints which are connected to that truss is in equilibrium.This is known as:
a) Method of joints        b) Section method
c) Scalar field method   d) Vector equilibrium method
9. How many equilibrium equations are used in method of sections?
   a) 2     b) 4       c) 3      d) 5
10.In method of sections, what is the maximum no. of unknown members through which the imaginary section can pass?
 a) 1      b) 2       c) 3      d) 4
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