1. **Problem Statement:**
We have a beam with a uniformly distributed load (UDL) $w = 10$ kN/m over the first 2 meters from the left support A, and a point load of 50 kN downward at the middle-right of the beam. The beam has supports at A (left) and B (right). We need to find the reactions at supports A and B.
2. **Given:**
- Uniformly distributed load $w = 10$ kN/m over length $L_1 = 2$ m
- Point load $P = 50$ kN at some point on the beam
- Beam length is not fully specified, but we assume the total length $L$ is known or can be considered as $L = 2 + x$ meters, where $x$ is the remaining length to support B.
3. **Step 1: Calculate the total load from the UDL**
The total load from the UDL is:
$$ W = w \times L_1 = 10 \times 2 = 20 \text{ kN} $$
This load acts at the midpoint of the 2 m segment, i.e., 1 m from support A.
4. **Step 2: Define reaction forces at supports**
Let $R_A$ be the reaction at support A and $R_B$ be the reaction at support B.
5. **Step 3: Apply equilibrium equations**
- Sum of vertical forces:
$$ R_A + R_B = W + P = 20 + 50 = 70 \text{ kN} $$
- Sum of moments about A (taking counterclockwise as positive):
Assuming the point load is at distance $d$ from A (to be specified or assumed), the moment equation is:
$$ R_B \times L = W \times 1 + P \times d $$
6. **Step 4: Solve for $R_B$ and $R_A$**
Rearranged moment equation:
$$ R_B = \frac{W \times 1 + P \times d}{L} = \frac{20 \times 1 + 50 \times d}{L} $$
Then,
$$ R_A = 70 - R_B $$
7. **Note:**
To fully solve, the total length $L$ and the position $d$ of the point load must be known. If the point load is at the midpoint of the beam, and the beam length is $L = 2 + 2 = 4$ m, then $d = 3$ m (2 m + 1 m into the second segment).
8. **Example with $L=4$ m and $d=3$ m:**
$$ R_B = \frac{20 \times 1 + 50 \times 3}{4} = \frac{20 + 150}{4} = \frac{170}{4} = 42.5 \text{ kN} $$
$$ R_A = 70 - 42.5 = 27.5 \text{ kN} $$
**Final answer:**
$$ R_A = 27.5 \text{ kN}, \quad R_B = 42.5 \text{ kN} $$
---
"slug": "beam reactions",
"subject": "structural engineering",
"desmos": {"latex": "y=0", "features": {"intercepts": true, "extrema": true}},
"q_count": 1
Beam Reactions 6977F1
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