u(x) = u cos (alpha) and
u(y) = u sin (alpha)
Say after time t it has velocity v making angle beta with horizontal.
v(x) = u(x) = u cos (alpha) and
v(y) = v sin (beta) = u sin (alpha) - gt
v= [(vx) ^2 + (vy) ^2]^1/2
=[u^2 +(gt) ^2 -2utsin (alpha)] ^1/2
Easy when you have t.