A boat, whose speed in still water is 8.0 m/s, crosses a river with a current of 6.0 m/s. If the boat heads perpendicular to the current, what is the speed of the boat relative to an observer standing on the shore as it crosses the river?

A.) 5.3 m/s B.) 8.0 m/s C.) 6.0 m/s D.) 10.0 m/s

D. 10m/s

Given,

speed of boat () = 8.0m/s

speed of river current () = 6.0m/s

Since the boat travels perpendicular to the current;

The resultant speed (v) of the boat, relative to an observer, will be the vector sum of the individual speeds of the boat and the current. i.e

v =  -------------------------(i)

Substitute the values of and into equation (i)

v =  

v =

v =

v = 10m/s

Therefore, the speed of the boat relative to an observer standing on the shore as it crosses the river is 10m/s.

answer( sicar );