Find the mass and center of mass of the lamina

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SUMMARY

The mass of the lamina occupying the region D = {(x, y) | 0 ≤ x ≤ 1, −1 ≤ y ≤ 1} with the density function ρ(x, y) = 7xy² is calculated using the formula m = ∫∫_D ρ(x, y) dA, resulting in a mass of 7/3. The center of mass is determined by the equations \(\overline{x} = \frac{1}{m} \iint_D x \rho(x, y) dA\) and \(\overline{y} = \frac{1}{m} \iint_D y \rho(x, y) dA\). A participant reported a center of mass of (80/9, 0), which was identified as incorrect, indicating a need for detailed working to identify errors.

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carl123
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Find the mass and center of mass of the lamina that occupies the region D and has the given density function ρ.
D = {(x, y) | 0 ≤ x ≤ 1, −1 ≤ y ≤ 1}; ρ(x, y) = 7xy2

I got my mass to be 7/3 but I'm not sure how to go about finding the center of mass
 
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The mass of the lamina is given by the formula $$m=\iint_D \rho (x, y)dA$$ and the center of mass of the lamina is $(\overline{x}, \overline{y})$ where $$\overline{x}=\frac{1}{m}\iint_D x \rho (x, y)dA \ \ \text{ and } \ \ \overline{y}=\frac{1}{m} \iint_D y \rho (x, y)dA$$
 
mathmari said:
the center of mass of the lamina is $(\overline{x}, \overline{y})$ where $$\overline{x}=\frac{1}{m}\iint_D x \rho (x, y)dA \ \ \text{ and } \ \ \overline{y}=\frac{1}{m} \iint_D y \rho (x, y)dA$$

Thanks for your reply, I got (80/9 , 0) as my center of mass but it appears to be wrong, not sure why
 
carl123 said:
Thanks for your reply, I got (80/9 , 0) as my center of mass but it appears to be wrong, not sure why

If you show your working, then perhaps it can be found where you went wrong, and how to correct it. If you simply say, "I got such and such and it is wrong, but I don't know why," this doesn't give us anything with which we can help. :)
 

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