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Grade 11Modern Physics

A Boat having a speed of 5 km per hour in stillwater crosses a river of width 1 km along the shortest possible path in 15 minutes the speed of the river in kilometre per horse

Profile image of Akshay kumar
8 Years agoGrade 11
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1 Answer

Profile image of Arun
8 Years ago
 

let the velocity of the river be x. the velocity of the river will be in the horizontal direction

 

velocity of boat in still water is 5km/hr. As the width of the river is 1 km and time taken by the boat to cross the river along the shortest path is 15 min therefore the velocity of the boat is=  1*60/15= 4km/hr

 

 according to the figure the velocity of the river is along  AB . By applying triangle law of vector addition the value of AB comes to be 3km/hr

 

1590_22392_line.jpg

 

 

Regards

Arun (askIITians forum expert)