Photo AI
FIGURE 7.1 below is a diagram of a steel framework - NSC Mechanical Technology Welding and Metalwork - Question 7 - 2022 - Paper 1
Question 7
FIGURE 7.1 below is a diagram of a steel framework. Answer the questions that follow. (Use Bow's notation.) Scale: Space diagram: 10 mm = 1 m Force/Vector diag... show full transcript
Worked Solution & Example Answer:FIGURE 7.1 below is a diagram of a steel framework - NSC Mechanical Technology Welding and Metalwork - Question 7 - 2022 - Paper 1
Step 1
7.1.1 Draw the space diagram and label the spaces. (Use Bow's notation.) Indicate the nature of each member on the space diagram.
Answer
To create the space diagram using Bow's notation, start by labeling points A, B, C, and D as shown in the diagram. The space diagram will include:
- Member AB: A strut
- Member AC: A strut
- Member BD: A tie
- The applied loads are:
- 300 N acting horizontally on members AB and AC from both ends, and
- 600 N acting vertically downward towards point D.
The angles at points A and C should be indicated as 30°.
Step 2
7.1.2 Determine graphically the magnitude of each member of the framework and indicate the nature of each member on the space diagram.
Answer
To find the magnitudes of the members, utilize the method of joints or graphical vector addition:
- Calculate the Force in Member AB and AC: Using the equilibrium of joint B (considering horizontal and vertical forces), establish the relationships:
- Horizontal balance: 300 N (left) = 300 N (right)
- Vertical balance: The resultant of forces in members BD must equal the vertical load (600 N down):
- Using trigonometry within the 30° angles, calculate the forces using: .
This can yield approximate values of the forces:
- Member AB: 510 N
- Member AC: 590 N
- Member BD (tie): 600 N
- Nature:
- Members AB and AC are in compression while member BD is in tension.