# 力学代写 mechanics代考2023

## 力学代写mechanics

### 统计力学Statistical mechanics代写

• Theory of relativity相对论
• Quantum mechanics量子力学

## 力学的相关

The history and development of differential geometry as a discipline can be traced back at least to the ancient classics. It is closely related to the development of geometry, the concepts of space and form, and the study of topology, particularly manifolds. In this section we focus on the history of the application of infinitesimal methods to geometry, and then on the idea of tangent spaces, and finally on the development of the modern formalism of the discipline in terms of tensors and tensor fields.

## 力学相关课后作业代写

Hooke’s law, a constitutive equation for a linear, elastic material, can be written in general form as:
$$\sigma_{i j}=\lambda \varepsilon_{k k} \delta_{i j}+2 \mu \varepsilon_{i j} \text { where } \lambda \text { and } \mu \text { are Làme constants. }$$
a) Expand Hooke’s Law. How many independent equations are there?

a) Hooke’s law
$$\sigma_{i j}=\lambda \varepsilon_{k k} \delta_{i j}+2 \mu \varepsilon_{i j}$$
where
$$\delta_{i j}=\left{\begin{array}{l} 1, \mathrm{i}=\mathrm{j} \ 0, \mathrm{i} \neq \mathrm{j} \end{array}\right.$$
For $i=1$
\begin{aligned} & \sigma_{11}=\lambda\left(\varepsilon_{11}+\varepsilon_{22}+\varepsilon_{33}\right)+2 \mu \varepsilon_{11} \ & \sigma_{12}=2 \mu \varepsilon_{12} \ & \sigma_{13}=2 \mu \varepsilon_{13} \end{aligned}

For $\mathrm{i}=2$
\begin{aligned} & \sigma_{21}=2 \mu \varepsilon_{21} \ & \sigma_{22}=\lambda\left(\varepsilon_{11}+\varepsilon_{22}+\varepsilon_{33}\right)+2 \mu \varepsilon_{22} \ & \sigma_{23}=2 \mu \varepsilon_{23} \end{aligned}
For $\mathrm{i}=3$
\begin{aligned} & \sigma_{31}=2 \mu \varepsilon_{31} \ & \sigma_{32}=2 \mu \varepsilon_{32} \ & \sigma_{33}=\lambda\left(\varepsilon_{11}+\varepsilon_{22}+\varepsilon_{33}\right)+2 \mu \varepsilon_{33} \end{aligned}