1. **Problem Statement:**
Calculate the polar moment of inertia $J$ for a hollow circular tube with outer diameter $D_o = 2$ in, inner diameter $D_i = 1.5$ in.
2. **Formula:**
The polar moment of inertia for a hollow circular shaft is given by:
$$J = \frac{\pi}{32} \left(D_o^4 - D_i^4\right)$$
3. **Explanation:**
- $D_o$ is the outer diameter.
- $D_i$ is the inner diameter.
- The formula subtracts the inner hollow part's moment from the outer solid cylinder's moment.
4. **Calculation:**
Calculate $D_o^4$ and $D_i^4$:
$$D_o^4 = 2^4 = 16$$
$$D_i^4 = 1.5^4 = (1.5)^4 = 5.0625$$
5. Substitute values into the formula:
$$J = \frac{\pi}{32} (16 - 5.0625) = \frac{\pi}{32} \times 10.9375$$
6. Simplify:
$$J = 0.09817477 \times 10.9375 = 1.074 \text{ in}^4$$
7. **Answer:**
The polar moment of inertia $J$ is approximately $1.074$ in$^4$.
This corresponds to option B.
Polar Moment
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