Velocity and acceleration with vector calculus

[Win_odd Dhamnekar]

The velocity of a boat relative to water is represented by \(\displaystyle 3\hat{?} + 4\hat{?}\) and that of water relative to earth is \(\displaystyle \hat{?}− 3\hat{?}\) . What is the velocity of the boat relative to earth if \(\displaystyle \hat{ ?}\) and \(\displaystyle \hat{?}\) represent one KM an hour east and north respectively?

How to answer this question?

 

[Dr.Peterson]

The velocity of a boat relative to water is represented by \(\displaystyle 3\hat{?} + 4\hat{?}\) and that of water relative to earth is \(\displaystyle \hat{?}− 3\hat{?}\) . What is the velocity of the boat relative to earth if \(\displaystyle \hat{ ?}\) and \(\displaystyle \hat{?}\) represent one KM an hour east and north respectively?

How to answer this question?

Just add the vectors.

It's really the same idea as saying that if you walk 3 kph and I walk 2 kph faster than you (in the same direction), then my speed is 5 kph.