A man walking briskly in rain with speed v must slant his umbrella forward making an angle theta with the vertical. A student derives the following relation between theta and v: tantheta = v and checks that the relation has a correct limit : as vtoo, thetato0, as expected , (we are assuming there is no strong wind and that the rain falls vertically for a stationary man.) Do you think this relation can be correct ? If you, guess the correct relation.

A man walking briskly in rain with speed v must slant his umbrella for

1.	A man walking briskly in rain with speed v must slant his umbrella forward making an angle theta with the vertical. A student derives the following relation between theta and v: tantheta = v and checks that the relation has a correct limit : as vtoo, thetato0, as expected , (we are assuming there is no strong wind and that the rain falls vertically for a stationary man.) Do you think this relation can be correct ? If you, guess the correct relation.
Answer» Solution :tan `THETA` must be dimensionless . The CORRECT formula is tan`theta = v//v.` where v. is the SPEED of RAINFALL.