Final answer:
The work done by gravity on a raindrop falling at constant speed is calculated using the formula Work = weight x distance. The work done by air resistance is equal in magnitude but opposite in direction to maintain constant velocity, thus it is the negative value of the work done by gravity.
Step-by-step explanation:
The student's question involves the calculation of work done by different forces on a falling object, which is a concept in physics. Specifically, they are asking about the work done by gravity and air resistance on a raindrop as it falls a certain distance. Part (a) of the question requires us to calculate the work done by gravity, which can be determined by the formula Work = force x distance, where the force is the weight of the raindrop (weight = mass x gravitational acceleration).
For part (b), the work done by air resistance is equal but opposite to the work done by gravity when the raindrop falls at a constant speed. This is because the net work done on the raindrop must be zero for it to maintain constant velocity. So, the work done by air resistance would be negative of the work done by gravity.