In a double-slit experiment, two beams of coherent light traveling different paths arrive on a screen some distance away. what is the path difference between the two waves corresponding to the third bright band out from the central bright band?

In this case, the path difference in between two waves is two wavelengths. In this double-slit experiment, the two beams of coherent light travels in different paths making the third bright band a destruction. So the difference is 2 wavelengths in between 2 waves. 

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