Velocity of the boat with respect to Earth is 5 m/s 56.31° north of east
Step-by-step explanation:
A boat heads north in still water at 4.5 m/s directly across a river that is running east at 3.0 m/s.
Let north be positive y axis and east be positive x axis.
We have
Velocity of boat = 4.5 j m/s
Velocity of river = 3 i m/s
Velocity of the boat with respect to Earth = 3 i + 4.5 j
That is 56.31° north of east.
Velocity of the boat with respect to Earth is 5 m/s 56.31° north of east