Atennis ball with a mass of 0.1kg falls off the roof of a building 10.4 meters tall. how long does it take for the ball to hit the ground?

The key formula ==>            H = 1/2 G T²

                                         10.4 = 1/2 (9.8) T²

Divide each side by  4.9 :  T² = 10.4 / 4.9

                                           T = √ (10.4/4.9) = 1.46 seconds .

The mass of the ball doesn't make any difference.  If not for air resistance,
a feather and a school bus, dropped from the same height at the same time,
would fall together, and hit the ground at the same time.  We've known this
for roughly 600 years now, and I suspect you learned it in the same high
school class where your question came from.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j