wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A boat, which has a speed of 5 km/h in still water, crosses a river of width 1 km along the shortest possible path in 15 minutes. What is the magnitude of velocity of the river water?

A
5 km/h
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
4 km/h
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
3 km/h
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
6 km/h
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 3 km/h
The speed of the boat in still water =vb=5 km/h
Width of the river =s=1 km
Time taken =t=15 minutes=14 h
Speed of the boat w.r.t the river =vbr=st=114=4 km/h
From the definition of relative velocity, we have
vbr=vbvr
Hence |vbr|2=|vb|2+|vr|2vr=(5242)=3 km/h
Hence the correct option is (c).

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Relative Motion in 2D
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon