Worked example - circular orbit radius and period for a satellite. Given: Earth mass M = 5.97 x 10^24 kg, satellite angular momentum per unit mass h = l/m = 5.0 x 10^10 m^2/s. Step 1: circular orbit at V_eff minimum: dV_eff/dr = k/r^2 - l^2/(m r^3) = 0 with k = G M m. Per unit mass: r_0 = h^2/(G M) = (25 x 10^20)/(6.67 x 10^-11 x 5.97 x 10^24) = 6.28 x 10^6 m ~ 6280 km - just below Earth's surface! (This h is too small for orbit; real LEO needs h ~ 5.3 x 10^10.) Step 2: orbital speed v = h/r_0 = 7962 m/s; period T = 2 pi r_0/v = 4956 s ~ 82.6 min. Raising h to 5.35 x 10^10 gives r_0 = 7190 km (altitude ~810 km), T ~ 101 min - a realistic LEO.