Question

obtain an expression for the radial velocity of objects in the galaxy as a function of their galactic longitude . for 5marks

Answer 1

$v_r =θv_0 cos l–Δvsin l$

$v_r ={v_0\over R_0} r {sinl} cosl−{dv \over dR} rsinlcosl$

$v_r =r {sinl} cosl ({v_0\over R_0} −{dv \over dR})$

$v_r =Аr {sin2l}$

where

$A ={1 \over 2} ({v_0\over R_0} −{dv \over dR})$  is Oort's first (sheer) constant