A boat is sailing along the river at a current speed of V1 = 1m / s, the speed of which relative to the water is V2 = 2m / s.

A boat is sailing along the river at a current speed of V1 = 1m / s, the speed of which relative to the water is V2 = 2m / s. Find the speed of the boat relative to the bank if: a) the boat is sailing with the river flow b) against the river flow c) at an angle of 90 ° to the river flow.

Given:

v1 = 2 meters per second – boat speed;

v2 = 1 meter per second – the speed of the river.

It is required to determine the speed of the boat relative to the bank in three cases: when the boat is sailing along the river, when the boat is sailing against the current of the river, and when the boat is sailing at an angle of 90 degrees to the course of the river.

1) when the boat is sailing along the river:

v = v1 + v2 = 2 + 1 = 3 meters per second.

2) when the boat is sailing against the stream of the river:

v = v1 – v2 = 2 – 1 = 1 meter per second.

3) when the boat is sailing at a 90 degree angle:

v = (v1 ^ 2 + v2 ^ 2) ^ 0.5 = (2 ^ 2 + 1 ^ 2) ^ 0.5 = (4 + 1) ^ 0.5 = 5 ^ 0.5 = 2.2 m /with.

Answer: downstream – 3 m / s, upstream – 1 m / s, at an angle – 2.2 m / s.