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Grade 11General Physics

Q.A person is standing on road by holding his umbrella at right abngle to the horizontal surface in order to protect himself from rain falling at a sped of 10m/s whereas the velocity of wind is 0. Suddenly wind begins to flow at speed of 20m/s towards 30 deg south of west. Now by what angle the person has to turn his umbrela in order to protect himself from rain.
Ans=tan(2)

Profile image of jiten
8 Years agoGrade 11
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2 Answers

Profile image of Arun
8 Years ago
Dear student
 
Velocity of Rain(Vr) = 10 m/sec
Velocity of Wind(Vw) = 20m/sec
The person have to turn his umbrella in the resultant of the velocity of rain and wind in order to protect himself from the rain.
                Then Angle = Velocity of Rain(Vr) / Velocity of Wind(Vw)
                              = ½
                              = tan-1(1/2)
 
I think answer given is wrong. Please check
 
Regards
Arun (askIITians forum expert)
Profile image of Gaurav Gupta
8 Years ago
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