Respuesta :
Answer:
[tex]v_{net} = 4\sqrt3 mph[/tex]
Explanation:
Since we know that the displacement of the boat in the direction of flow of the river must be zero
so we have to at such an angle with shore so that the component of velocity of boat along the direction of flow must be equal and opposite to the flow velocity of the water
so we will have
[tex]v cos\theta + v_r = 0[/tex]
[tex]8 mph cos\theta + 4 mph = 0[/tex]
[tex]cos\theta = -\frac{4 mph}{8 mph}[/tex]
[tex]cos\theta = -0.5[/tex]
[tex]\theta = 120 ^o[/tex]
Now the resultant velocity of the boat is in perpendicular to the flow of water
so we will have
[tex]v_{net} = v sin\theta[/tex]
[tex]v_{net} = 8 sin60[/tex]
[tex]v_{net} = 4\sqrt3 mph[/tex]
