Q4.33Long answer
A girl riding a bicycle with a speed of 5 m/s towards north direction, observes rain falling vertically down. If she increases her speed to 10 m/s, rain appears to meet her at 45° to the vertical. What is the speed of the rain? In what direction does rain fall as observed by a ground based observer? (Hint: Assume north to be î direction and vertically downward to be − ˆj . Let the rain velocity vr be a ˆi + b ˆj . The velocity of rain as observed by the girl is always vr − vgirl . Draw the vector diagram/s for the information given and find a and b. You may draw all vectors in the reference frame of ground based observer.)