Question

A river flows from south to north at 5.6 km/hr. On the west bank of this river, a boat launches and travels perpendicular to the current with a velocity of 7.7 km/hr due east. If the river is 1.6 km wide at this point, how far downstream does the boat land on the east bank of the river relative to the point it started at on the west bank?

Answer 1

Downstream displacement = 1.1648 km

Step-by-step explanation:

Given:

Speed of flow = 5.6 km/h

Speed of current upstream = 7.7 km/h

Increase in size = 1.6 km wide

Computation:

Total time to cross = Increase in size / Speed of current upstream

Total time to cross = 1.6 / 7.7

Total time to cross = 0.208 h

Downstream displacement = Speed of flow × Total time to cross

Downstream displacement = 5.6 × 0.208

Downstream displacement = 1.1648 km