1) A person swims in a river aiming to reach exactly on the opposite point on the bank of a river His speed of swimming is 0.5 m/s at an angle of 120° with the direction of flow of water. The speed of water is A) 1.0m/s B) 0.5m/s C) 0.25m/s D) 0.43m/s Answer: Option CExplanation:Let the speed of water = ¯u Speed of swimmer = ¯v = 0.5m/sec Angle between ¯u and ¯v is 120°. Then sinθ=¯u¯v = u0.5=12 or u=0.25ms-1