A boat is moving with a velocity `3 hat i+ 4hat j` with respect to ground. The water in the river is moving with a velocity `-3 hat i - 4 hat j` with respect to ground. The relative velocity of the boat with respect to water is.

Explanation

Velocity of boat w.r.t. ground, `vec v_(B)=3 hat I + 4 hat j`.
Relative velocity or boat w.r.t. water is,
` vec v _(BW) = vec _(B) -vec v_(W) = (3 hat I + 4 hat j) - (-3 hati -4 hat j)
`= 6 hat I + 8 hat j`