Kinematics Question 315
Question: A boat moves with a speed of 5 km/h relative to water in a river flowing with a speed of 3 km/h and having a width of 1 km. The minimum time taken around a round trip it’s [J&K CET 2005]
Options:
A) 5 min
B) 60 min
C) 20 min
D) 30 min
Show Answer
Answer:
Correct Answer: D
Solution:
For the round trip he should cross perpendicular to the river
$ \therefore $ Time for trip to that side $ =\frac{1km}{4km/hr}=0.25hr $ To come back, again he take 0.25 hr to cross the river. Total time is 30 min, he goes to the other bank and come back at the same point.
