Answer:
1)
2)
3)
4)
Explanation:
1)
We can use the following equation:

Here, the initial velocity in the y-direction is zero, the final y position is zero and the initial y position is 25 m.


2)
The equation of the motion in the x-direction is:



3)
The velocity in the y-direction of the stone will be:



Now, the velocity in the x-direction is 15 m/s then the velocity will be:

4)
The angle of this velocity is:
Then α=55.92° negative from the x-direction.
I hope it helps you!