Mass of M and M not needed and 10 stories is about 30 meters. So, this equation from kinematics will do. Velocity2 = velocity initial2 + 2acceleration gravity*distance There is no initial velocity,...
6m/s in the x direction, 9.9m/s in the y direction. 11.58 m/s total at an angle of 58.78 degrees above horizontal. This is assuming air resistance is negligible.
A theoretical answer can be derived if you ignore energy losses (such as air resistance). Assume the diver starts off with a downward velocity of zero, and accelerates under gravity with no energy...