Question

A man is holding an umbrella at an angle ${30^o}$ with a vertical lower end towards himself, which is an appropriate angle to protect him from rain for his horizontal velocity $10{\text{ }}m/s$. Then which of the following will be true?

A. Rain may be falling at an angle of ${30^o}$ with the vertical towards the left side.
B. Rain may be falling at an angle of ${30^o}$ with the vertical, towards the right side.
C. Rain may be falling vertically.
D. None of these

Answer 1

Hint:We will approach this question very much with our intuition. We will just observe the given situation and compare the given option with our practical knowledge and arrive at the answer by taking his velocity into consideration.

Complete answer:
We see that the person is holding the umbrella at an angle of ${30^o}$ with the vertical and are also told that he is able to save himself from getting wet.Thus, we can safely say that the rain is also falling at an angle ${30^o}$ with the vertical towards the left as if this is the case, then the umbrella will directly oppose the incoming rain and in turn will save the person from getting wet. Thus, one of the correct options is A.

Also, It is given that the person holds the umbrella close to his body. Thus, if the rain is falling vertically downwards, then this orientation of the umbrella would help the person from getting wet. Thus, C is also a correct option.

Hence, the correct answers are A and C.

Note:Students should be very much cautious while arriving at a conclusion as these types of questions are easy but approaching it casually can lead to a wrong answer. Students should never think that every question will have only one correct answer. They should always look out for every possible answer to the question. Here, the angle and the orientation of the umbrella. But there are few questions where we will be given the flow of the rain, orientation, angle of the fall of rain and will be asked to find the angle at which the umbrella should be held.