We study the motion of the ball on the two coordinating needles Ox and Oy, originated on the ground. On Ox the ball has a uniform straight motion with the velocity vx = vo and the equation of motion is x = vo * t, and on the ball Oy has a movement uniformly accelerated with acceleration g and no initial velocity on the axis Oy v_oy = 0 (free fall), so the equation of motion is y = h-gt² / 2.The equation of the trajectory is obtained by eliminating the time from the two equations. We hold t = x / vo => y = h-gx²/2vo².The trajectory is a parabola because y is a second degree function of x. Bila arrives on the ground when y = 0 => t =√(2h/g)=√(2*100/9.8)=√20.4=4.51 s
The ball will fall towards the rock at a distance d = vo * t =10*4.51≈45 m
The correct answer is e