Question

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

• A. $6\hat{i}+8\hat{j}$
• B. $8\hat{i}+8\hat{j}$
• C. $6\hat{i}+6\hat{j}$
• D. none of these

Answer 1

Answer: (A)

$ \vec{V}_{b} =3\hat{i} +4 \hat{j}, \vec{V}_{w} =-3\hat{i}-\hat{j}$
$\overrightarrow{V_{BA}} =\vec{V_{b}}-\vec{V_{w}}=6\hat{i}+8\hat{j}$