Recent content by Angela G

Sorry for being unclear, I have a planet that has a spin angular velocity ## \omega##, its rotation axis is in the z-direction. The planet is impacted nearly tangentially i.e the velocity of the object just before the impact, can be assumed to be nearly tangential, thus we chose the negative...

r is in the same direction as the radius of the planet(out from the centrum), and p is in the direction of the velocity, if we assume that the object is going to the planet from right to left as in the picture, then the momentum is in the negative y-axis. my reference frame is: the z-axis is...

HI! I tried to solve this exercise, by assuming that it is an inelastic collision, the planet is spherical, and that the rotation axis is parallel to the z-axis, see the figure attached. (1) before the collision, (2) after the collision.I started by assuming angular momentum conservation, which...

Thank you very much!

I wonder if someone please could explain what the relationship between a spectral line strength and gravity is? Does the equivalent width of e.g. Ca II decrease with increasing gravity? what kind of processes affects the strength of a line if we change the gravity of a star? Hope you can help me

yes, I'm sorry For solving a) I have to do it with the hydrostatic equilibrium equation, to determine the pressure and to determine the temperature I have to use the expression I got from the pressure and use the ideal gas law ## P = \frac{\rho k T}{\mu m_H}##, for solving c) I think I should...

to solve a) I used The equation of hydrostatic equilibrium $$ \frac{d P}{d r} = - \rho \frac{GM}{r^2} \iff dP = - \rho \frac{GM}{r^2}dr \Longrightarrow \int_{P_c}^0 dP = - \int_0^R \rho \frac{GM}{r^2} dr $$ I replaced M as ## \rho V ## and then I integrated both the left and right-hand sides and...

Thanks, for all your answers! I understand now

(P.S! this is an open question, feel free to answer)

ok, thank you 😊 😊 😊

it does not variate?

## \rho_f(\vec r,t)## decreases exponentially and ##\rho_f (\vec r, 0 ) is konstant with position

I got first $$ - \frac{\sigma_{\alpha} dt}{\epsilon_0 X_e} = \frac{1}{\rho_f} d \rho_f \Longrightarrow \int - \frac{\sigma_{\alpha} dt}{\epsilon_0 X_e} = \int \frac{1}{\rho_f} d \rho_f \Longrightarrow -\frac{\sigma_{\alpha} t}{\epsilon_0 X_e} = \ln( \rho_f) + c $$ and then $$...

Ok, Understan, How can I solve the DE? I think it is homogenius, right? Edit: nevermind

ok, if I do so then the divergens will be $$ \vec \nabla \cdot \vec J = \frac{\rho_f \sigma_{\alpha}}{\epsilon_0 X_e} $$ Then move ## \rho_f ## to the right side of the divergens and get $$ - \frac{\sigma_{\alpha}}{\epsilon_0 X_e} = \frac{1}{\rho_f} \frac{\partial \rho}{\partial t} $$ or...