Question

Reggie is in a boat on the south shore of a river that is 925 m wide. He starts his boat moving exactly north at a constant speed of 3.05 m/s. However, Reggie does not take into account a strong current in the river moving east at 1.20 m/s. By the time Reggie crosses the river, how far to the east have he and his boat drifted?

Answer 1

First, let's calculate the time, required to cross the river. If Reggie approaches the opposite shore with speed 3.05 m/s, he will cover the distance of 925 m in the following amount of time:

$$t = \dfrac{925m}{3.05m/s} \approx 303.28 s$$

If his side speed is 1.20 m/s, then, during this time he will find himself

$$L = 1.20m/s\cdot 303.28s = 363.94m$$

to the East from the point of departure.

Answer. 363.94m.