1. **Stating the problem:**
Determine the reaction forces at the supports of the first beam structure and then draw the diagrams of Normal force (N), Shear force (T), and Bending moment (Mf).
2. **Given data and setup:**
- Beam length: $1 + 3 + 1 = 5$ m
- Uniform distributed load (UDL): 100 N/m over the first 1 m from the left end
- Concentrated forces: 300 N at 1 m from left end, 200 N at 1 m from right end
- Beam is fixed at the right end
3. **Step 1: Calculate total load from UDL:**
$$\text{Load}_{UDL} = 100 \times 1 = 100 \text{ N}$$
4. **Step 2: Determine the position of the resultant of UDL:**
The resultant acts at the midpoint of the 1 m segment, i.e., at 0.5 m from the left end.
5. **Step 3: Define reaction forces:**
Let $R_A$ be the vertical reaction at the left end (if any), and $R_B$ be the reaction at the fixed right end (3 + 1 = 4 m from left end).
6. **Step 4: Apply equilibrium equations:**
- Sum of vertical forces:
$$R_A + R_B = 100 + 300 + 200 = 600$$
- Sum of moments about left end (taking counterclockwise positive):
$$-100 \times 0.5 - 300 \times 1 - 200 \times 4 + R_B \times 5 = 0$$
Calculate:
$$-50 - 300 - 800 + 5 R_B = 0$$
$$5 R_B = 1150$$
$$R_B = 230$$
7. **Step 5: Calculate $R_A$:**
$$R_A = 600 - 230 = 370$$
8. **Step 6: Draw diagrams:**
- Normal force (N) diagram: Since no axial loads are given, $N=0$ everywhere.
- Shear force (T) diagram: Starts at $R_A=370$ N, decreases by 100 N over first 1 m (UDL), drops by 300 N at 1 m, remains constant until 4 m, then drops by 200 N at 4 m, ends at $-R_B = -230$ N.
- Bending moment (Mf) diagram: Calculate bending moments at key points using shear force and loads.
**Final answer:**
$$R_A = 370 \text{ N}, \quad R_B = 230 \text{ N}$$
Normal force $N=0$ everywhere.
Shear and bending moment diagrams can be drawn based on these reactions and loads.
Beam Reactions 74F95C
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