physics
posted by Vasco .
A body is projected so that on its upward path it passes through a point x meters and y meters vertically from the point of projection. Show that if R is the range on the horizontal through point of projection the angle of elevation is arctan((y/x)(R/Rx)).

A body projected upward from the level ground at an angle of 50ยบ with the horizontal has an initial speed of 40 m/s. (a) How long will it take to hit the ground? (b) How far from the starting point will it strike? (c) At ehat angle with the horizontal will it strike?