Question

A man is travelling at 10.8kmph in a
topless car on a rainy day. He holds an
umbrella at an angle of 370 with the
vertical so that he does not wet. If rain
drops falls vertically downwards, what is
the rain velocity?​

Answer 1

Velocity of the rain = 4 m/s

Explanation:

Given: A man is traveling at 10.8 kmph in a topless car on a rainy day. He holds an umbrella at an angle of 37 degrees with the vertical so that he does not wet. Raindrops fall vertically downwards.

Find: The rain velocity.

Solution:

Please refer to the attached picture for the diagram. Vr represents the raindrops and Vm represents the motion of the car.

Hence we find that Vrm = Vr - Vm

tan 37∘ = Vm/ Vr = 3/4

10.8 / Vr = 3/4

Vr = 4/3 * 10.8 = 14.4 Kmph

     = 14.4 * 1000 / 60 * 60

 Vr  = 4 m/s