the velocity along the surface will not change!!!!!!!!..........
the velocity perpendicular to the surface, vapp = n(vactual perp. to surface)
= n(vsinφ)
=4/3 * 3v/5
=4v/5
now along the surface =vcosφ=4v/5
and perp. to the surface=4v/5
tanθ=[4v/5] / [4v/5]
θ=450