A plane is flying horizontally at 98m/s and releases an object which reaches the ground in 10s. The angle made by it while hitting the ground is:

Vertical component of velocity of the object while hitting the ground is vy=0+gt  =9.8×10=98m/s So the angle made by the object with the horizontal while hitting the ground.α=tan−1(vyvx)=tan−1(9898)=450                              (∴ux=vx=98m/s)