Question

A man standing on a road has to hold his umbrella at `30^(@)` with the vertical to keep the rain away. He throws the umbrella and starts running at 10km/hr. He finds that rain drop are hitting his head vertically. Find the speed of rain drops with respect to (a) road (b) the moving man.
A. 20 km/hr.
B. `10 sqrt(3) km//hr`.
C. `(10)/sqrt(3)km//hr`.
D. 10 km/hr.

Answer 1

Correct Answer - B
`tan 30^(@)=(v_(m))/(v_(rm))`
`v_(rm)=(10)/(1sqrt(3))=10sqrt(3) km//hr`.