By the term velocity of rain, we mean velocity with which raindrops fall relative to the ground. In absence of wind, raindrops fall vertically and in presence of wind raindrops fall obliqucly. Moreover raindrops acquire a constant terminal velocity due air resistance very quickly as they fall toward the carth. A moving man relative to himself observes an altered velocity of raindrops. Which is known as velocity of rain relative to the man. It is given by the following equation.
`vec(v)_(rm)=vec(v)_(r)-vec(v)_(m)`
A standstill man relative to himself observes rain falling with velocity, which is equal to velocity of the raindrops relative to the ground. To protect himself a man should his umbrella against velocity of raindrops relative to himself as shown in the following figure.

A man walks in rain at 72 cm/m due east and observes the rain falling vertically. When he stops, rain appears to strike his back at `37^(@)` from the vertical. Find velocity of raindrops relative to the ground.

Answer

120 cm/s