Assignment:
Its raining and your trying to decide whether or not to run or walk. If you walk you'll spend longer in the rain, but if you run you'll be running into the rain and potentially get wetter. The rain is falling with a velocity of which has both an x-component as it blows sideways and a y-component as it falls.
You move with a velocity of which only has an x-direction. If the rain is falling with a density and you have a top area of (which rain will fall onto) and a sideways area of (which rain will fall onto if it blows sideways or you move sideways into it), find an expression for how wet you would be when traveling a distance d, as a function of your velocity.