(^288) A Textbook of Engineering Mechanics
- A truss 15 m long is subjected to a point load of 10 kN as shown in Fig. 13.69. Find the forces
in the members 1, 2 and 3 of the truss.
Ans. 1 = 40 kN (Compression)
2 = 10 kN (Compression)
3 = 10 kN (Compression)
Hint. Pass vertical sections cutting the members 1, 2 and 3 and take moments about the
joint containing 100 kN load. Each time, all the members (except 1, 2 and 3) pass
through the joint about which moments are taken.QUESTIONS
- What is a ‘frame’? Discuss its classification.
- State clearly the difference between a perfect frame and an imperfect frame.
- How would you distinguish between a deficient frame and a redundant frame?
- What are the assumptions made, while finding out the forces in the various members of a
framed structure? - Name the methods, which are employed, for finding out the forces in a frame.
- What is the difference between a simply supported frame and a cantilever frame?
Discuss the method of finding out reactions in both the cases.
OBJECTIVE TYPE QUESTIONS
- A framed structure is perfect, if the number of members are .....(2j – 3), where j is the
number of joints.
(a) less than (b) equal to (c) greater than (d) either (a) or (c) - A framed structure is imperfect, if the number of members are .....(2j – 3), where j is the
number of joints.
(a) less than (b) equal to (c) greater than (d) either (a) or (c) - A redundant frame is also called ......frame
(a) perfect (b) imperfect (c) deficient (d) none of these - A framed structure of a triangular shape is
(a) perfect (b) imperfect (c) deficient (d) redundant - In a cantilever truss, it is very essential to find out the reactions before analyzing it.
(a) agree (b) disagree
ANSWERS
- (b) 2. (d) 3. (b) 4. (a) 5. (b)
Fig. 13.69.