Four trains travel on different sections of a long straight track. Taking noth to be the positive direction, rank the trains in order by velocity, from most negative to most positive. The trains move as follows: Train A moves north with a speed of 10 m/s. Train B heads south and covers 900 m in 1 minute. Train C also heads south and has twice the speed of train A. Train D travels north and covers 24
m in 2 s.

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