Edits to “Statement”, “Solution”

crico edited
revision #12596 newer →
@@ -1,39 +1,58 @@
### Statement
−$5.4.17.$ [Insert problem description here]
+$5.4.16*.$ [Insert problem description here]
__Example Statement__:
−$1.1.1.$ Determine the coordinate $x(t)$ of a body as a function of time $t$, given that its acceleration is defined as $a(t) = bt$, where $b$ is a constant.
+$1.1.1.$ Between two flat parallel plates located at a distance δ from each other, there
+is a monatomic gas (the free path of atoms is much longer than δ). Estimate
+the heat flux density if the temperature of the plates is maintained at T and
+T + ∆T, respectively, and the unit volume of gas contains n' atoms; µ is the
+mass of the atom
### Solution
[Your solution should be placed here]
__Example Solution__:
−The acceleration of the body defined by
+Heat flow is defined by
−$$a(t) = bt$$
+
+$$J =\frac{ΔE}{A*t} $$
−We know that acceleration is the time derivative of velocity:
+We know that the change of the energy is given by
−$$a(t) = \frac{d v(t)}{d t}$$
+$$ΔE = \frac{nRΔT}{\gamma-1}$$
−To find the velocity $v(t)$, we integrate $a(t)$ with respect to time:
+Where (n) is the number of moles
−$$v(t) = \int a(t) \, dt = \int b t \, dt$$
+We know that Heat flow then
−If the initial velocity is $v(0) = 0$, then the velocity becomes:
+$$J = \frac{nRΔT}{(\gamma-1)A*t}$$
−$$v(t) = \frac{b t^2}{2}$$
+We know that the time is given by because (the free path of atoms is much longer than δ) furthermore λ>>δ therefore the average collision between the molecules will be δ:
−Likewise, integrate $v(t)$ with respect to time:
+$$t = \frac{δ}{v}$$
−$$x(t)= \int v(t) \, dt = \frac{b}{2} \int t^2 \, dt$$
+Likewise:
−From where the coordinate from time, considering the initial conditions:
+$$J = \frac{nRΔTv}{(\gamma-1)A*δ}$$
−$$\boxed{x(t)=\frac{bt^3}{6}}$$
+Now we have to:
+
+$$A*δ=V$$
+
+So from the previous equations we have to:
+
+$$J = \frac{nRΔTv}{(\gamma-1)V}$$
+
+Another way to write this equation is:
+
+$$J = \frac{n'KΔTv}{(\gamma-1)}$$
+
+Where (n') is the number of the atoms
+
+$$v=\
#### Answer
unchanged lines 5