1, exercise time t=(2y/g) 1/2, which is usually expressed as (2h/g) 1/2.

2. Closing speed vt = (VX1+vy1)1/2 = [v01+(gt)1]1/2.

The angle between the closing speed direction and the horizontal plane is β: tgβ = vy/VX = gt/v0.

3. Combined displacement: s = (x1+y1)1/2.

The included angle α between the displacement direction and the horizontal plane: tgα = y/x = gt/2v0.

4. Horizontal acceleration: ax = 0；; Vertical acceleration: ay = g.