JEE Main20198 Apr 2019Morning ShiftPhysicsMathematics in PhysicsActual
Ship A is sailing towards north-east with velocity) v → = 30 i ^ + 50 j ^ km h - 1 where i ^ points east and j ^ , north. The ship B is at a distance of 80 k m east and 150 k m north of Ship A and is sailing towards the west at 10 k m h - 1 . A will be at the minimum distance from B in:
Options
- A4.2 h
- B3.2 h
- C2.6 h
- D2.2 h
Correct answer
C. 2.6 h
Step-by-step solution
v → r e l = v → 1 - v 2 = 40 i + 50 j r → r e l = r → 1 - r → 2 = - 80 i - 150 j t m i n = v → r e l ·   r → r e l v → r e l 2 = - 3200 - 7500 40 2 + 50 2 2 t m i n = 10700 4100 = 107 41 = 2.6   h