Kinematics Question 649
Question: A boat which has a speed of 5 km/hr in still water crosses a river of width 1 km along the shortest possible path in 15 minutes. The velocity of the river water in $ km/hr $ it’s
Options:
A) 3
B)4
C) $ \sqrt{21} $
D)1
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Speed along the shortest path $ =\frac{1}{15/60}=\text{4 km/hr} $
Speed of water $ \text{v}=\sqrt{5^{2}-4^{2}}=3\text{ km/hr} $
