Question

найти скорость человека относительно плота, если скорость течения реки 4 м/с, а скорость человека относительно берега 2,5 м/с. Человек перемещается перпендикулярно течению реки

Answer 1

V=корень квадратный из 2.5^2+4^2=4.7м/с 

Answer 2

Calculation of the Person's Speed Relative to the River Bank

To find the speed of a person relative to the river bank, given the speed of the river current and the speed of the person relative to the river bank, we can use vector addition.

Let's denote the speed of the river current as Vr (4 m/s) and the speed of the person relative to the river bank as Vp (2.5 m/s). Since the person is moving perpendicular to the river current, we can consider their velocities as vectors at right angles to each other.

To find the person's speed relative to the river bank, we can use the Pythagorean theorem to calculate the magnitude of the resultant vector:

Vr^2 + Vp^2 = Vr_p^2

Substituting the given values:

(4 m/s)^2 + (2.5 m/s)^2 = Vr_p^2

Simplifying the equation:

16 + 6.25 = Vr_p^2

22.25 = Vr_p^2

Taking the square root of both sides:

Vr_p = √22.25 ≈ 4.71 m/s

Therefore, the speed of the person relative to the river bank is approximately 4.71 m/s.