1. **State the problem:** We need to find the weight of 5 washers. Each washer is a cylindrical ring with an inner diameter of $\frac{1}{4}$ inch, outer diameter of $\frac{3}{4}$ inch, thickness of $\frac{1}{4}$ inch, and density $0.285$ pounds per cubic inch.
2. **Formula for volume of a washer:** The volume $V$ of a washer (a cylindrical ring) is the volume of the outer cylinder minus the volume of the inner cylinder:
$$V = \pi h (R^2 - r^2)$$
where $h$ is thickness, $R$ is outer radius, and $r$ is inner radius.
3. **Calculate radii:**
$$R = \frac{3}{4} \div 2 = \frac{3}{8}$$
$$r = \frac{1}{4} \div 2 = \frac{1}{8}$$
4. **Calculate volume of one washer:**
$$V = \pi \times \frac{1}{4} \times \left(\left(\frac{3}{8}\right)^2 - \left(\frac{1}{8}\right)^2\right)$$
Calculate squares:
$$\left(\frac{3}{8}\right)^2 = \frac{9}{64}, \quad \left(\frac{1}{8}\right)^2 = \frac{1}{64}$$
Subtract inside parentheses:
$$\frac{9}{64} - \frac{1}{64} = \frac{8}{64} = \frac{1}{8}$$
So volume:
$$V = \pi \times \frac{1}{4} \times \frac{1}{8} = \pi \times \frac{1}{32}$$
5. **Calculate volume numerically:**
$$V = \pi \times \frac{1}{32} \approx 3.1416 \times 0.03125 = 0.09817 \text{ cubic inches}$$
6. **Calculate weight of one washer:**
Weight $= \text{density} \times \text{volume} = 0.285 \times 0.09817 = 0.02797$ pounds
7. **Calculate weight of 5 washers:**
$$5 \times 0.02797 = 0.13985$$
8. **Round to nearest hundredth:**
$$0.13985 \approx 0.14$$
**Final answer:** The weight of 5 washers is approximately **0.14 pounds**.
Washer Weight 78C964
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