Task id12648

What must be the minimum frictional force between the car's wheels and the road so that it can move at a speed of v = 30 m/sec in vertical rain? The mass of a raindrop is m = 0.1 g. Every second, two drops of rain fall on 1 cm2 of a horizontal surface (a = 2). The surface area of the car wetted by rain is S = 5 m2. Assume that the entire surface is wetted by rain evenly.