Question 1065580
Velocity is a vector. 
Let east be positive x, north positive y.
{{{V[2]}}}=({{{0}}},{{{50}}})
{{{V[1]}}}=({{{0}}},{{{20}}})
{{{DELTA*V=V[2]-V[1]}}}
{{{DELTA*V}}}=({{{0}}},{{{50}}})-({{{0}}},{{{20}}})
{{{DELTA*V}}}  =({{{0}}},{{{30}}})