Physics Galaxy Discussion Questions | Solutions _best_

Open Volume 1. Go to the "Centre of Mass" discussion questions. Find the problem about the man walking on a boat. Do not look at the solution. Draw the system. Watch the center of mass. The universe will make sense.

| Discussion Topic | Core Physics Concept | Mathematical Takeaway | |----------------|----------------------|------------------------| | Rotation curves | Dark matter halo density profile | (\rho(r) \propto r^-2) → (v(r) = \textconst) | | Spiral arms | Density waves & pattern speed | (\Omega_p \neq \Omega(r)); wave dispersion relation | | AGN energy | Gravitational accretion efficiency | (\eta \sim 0.05-0.4), (L \leq L_\textEdd) | | Hubble expansion | Metric expansion of space | (v = H_0 d) from (ds^2 = -c^2 dt^2 + a(t)^2 d\Sigma^2) | physics galaxy discussion questions solutions

Solution

$$ \Delta H = \Delta U + \Delta(PV) $$

Known scaling: $\theta_E = 1'' \left( \fracM10^11 M_\odot \right)^1/2 \left( \fracD_ls/D_s0.5 \right)^1/2 \left( \fracD_l1,\textGpc \right)^-1/2$. Open Volume 1