Answer:
a) vboat = 5.95 m/s b) vriver= 1.05 m/s
Explanation:
a) As observed from the shore, the speed of the boats can be expressed as the vector sum, of the boat speed relative to the water and the river speed relative to the shore, as follows:
vb₁s = vb₁w + vrs
In one case, the boat is moving in the same direction as the water:
vb₁s = vb₁w + vrs = 7.0 m/s (1)
For the other boat, it is clear that is moving in an opposite direction:
vb₂s = vb₂w - vrs = 4.9 m/s (2)
As we know that vb₁w = vb₂w, adding both sides, we can remove the river speed from the equation, as follows:
vb₁w = vb₂w =
b) Replacing this value in (1) and solving for vriver, we have:
vriver = 7.0 m/s - 5.95 m/s = 1.05 m/s
(we could have arrived to the same result subtracting both sides in (1), and (2))