To a man walking at the rate of 3 kmlh the rain appears to fall vertically. When he increases his speed to 6 kmlh it appears to meet him at an angle of 45° with vertical. Find the angle made by the velocity of rain with the vertical and its value.

Explanation

From the diagram `tan45^(@) =3/y`………..(i)
and `tan theta =3/y`……(2)
From (1) and (2) `theta =45^(@)` and
`therefore sin 45^(@) =3/V_(R), 1/sqrt(2) =3/V_(R)`
`V_(R) =3sqrt(2)` kmph