Question

Raindrops make an angle q with the vertical when viewed through a moving train window (Fig. 3-48). If the speed of the train is vt , what is the speed of the raindrops vd in the reference frame of the Earth in which they are assumed to fall vertically?

Answer 1

If θ is the angle the rain makes with the vertical (from the train's reference frame),

tanθ = (velocity of train) / (velocity of raindrops in Earth frame)