Linear Mass Density Problem

In summary, a long thin rod with linear mass density of λ=0.300x^2+0.500 in kg/m is placed along the x-axis with one end at x=2.00 m and the other at x=3.00 m. To calculate the mass of the rod, the formula m = ∫ λ(x) dx is used, and for finding the center of mass, the formula x_CM= (1/m)∫ x λ(x) dx can be used.
  • #1
AstroturfHead
6
0
I'm having a hard time with this.
A long thin rod lies along the x-axis. One end is at x=2.00 m and the other at x=3.00 m. Its linear mass density λ = 0.300 x2+ 0.500, in kg/m. Calculate mass of the rod.

Can anybody help?
 
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  • #2
I take it you mean [itex]\lambda = .300x^2 + .500[/itex]?

Note that

[tex]m = \int_{x_1}^{x_2}\lambda(x) dx[/tex].

--J
 
  • #3
But then how would I find the center of mass?
 
  • #4
The center of mass is just the weighted average of the density. You really should be able to look these formulas up on your own, or memorize them.

[tex]x_{CM}= \frac{1}{m}\int_{x_1}^{x_2} x \lambda(x) dx[/tex]

--J
 

1. What is linear mass density?

Linear mass density is a measure of the mass per unit length of a one-dimensional object, such as a wire or string. It is commonly denoted by the symbol λ (lambda) and is expressed in units of kilograms per meter (kg/m).

2. How is linear mass density calculated?

Linear mass density is calculated by dividing the mass of the object by its length. The formula is λ = m / L, where λ is the linear mass density, m is the mass, and L is the length of the object.

3. What is the difference between linear mass density and linear density?

Linear mass density and linear density are often used interchangeably, but there is a subtle difference between the two. Linear mass density is the mass per unit length of a one-dimensional object, while linear density refers to the number of particles per unit length of a one-dimensional object.

4. How is linear mass density related to linear density?

Linear mass density and linear density are related through the density of the material of the object. Linear mass density is equal to the linear density multiplied by the density of the material. The formula is λ = ρ * γ, where ρ is the density of the material and γ is the linear density.

5. What are some common applications of linear mass density?

Linear mass density is commonly used in engineering and physics to calculate the strength and stability of structures, such as cables and bridges. It is also used in the textile industry to measure the thickness and strength of fibers. Additionally, linear mass density is important in the study of waves, such as sound and light, as it affects the speed and frequency of the waves.

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