Find the mass and center of mass of the lamina

In summary, the mass of the lamina is 7/3 and the center of mass is (80/9, 0). To find the center of mass, we use the formulas for $\overline{x}$ and $\overline{y}$ in the given region D and density function ρ. It is important to show your working in order to identify and correct any errors.
  • #1
carl123
56
0
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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  • #2
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 $$\overline{x}=\frac{1}{m}\iint_D x \rho (x, y)dA \ \ \text{ and } \ \ \overline{y}=\frac{1}{m} \iint_D y \rho (x, y)dA$$
 
  • #3
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
 
  • #4
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. :)
 

FAQ: Find the mass and center of mass of the lamina

What is the definition of mass and center of mass?

Mass is a measure of the amount of matter in an object, while center of mass is the average position of all the mass in an object.

How is mass and center of mass different?

While mass is a scalar quantity, center of mass is a vector quantity. Mass has a single value for an object, while center of mass has both magnitude and direction.

What is a lamina?

A lamina is a two-dimensional object with a uniform thickness, such as a sheet of metal or paper.

How do you find the mass of a lamina?

The mass of a lamina can be found by multiplying its density by its area. Density is a measure of how much mass is contained in a given volume.

How do you find the center of mass of a lamina?

The center of mass of a lamina can be found by dividing the total moment of the lamina by its total mass. The moment is the product of the mass and the distance from a chosen axis.

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