Question

В двух неподвижных лодках находятся мальчики. Масса первой лодки с мальчиком составляет 120кг, второй-80кг. После того как мальчик на второй лодке оттолкнулся от себя первую лодкк, его лодка приобрела скорость, равную 1,5 м/с. Какую скорость приобрела первая лодка? помогите пожалуйста

Answer 1

M1=120
m2=80
ЗСИ (закон сохранения импульса)
0=m1*V1+m2*V2
0=120*1.5+80*x
x=-120*1.5/80=2.25
Ответ: 2.25

Answer 2

Problem Analysis

In this problem, we have two stationary boats with boys on them. The mass of the first boat with the boy is 120 kg, and the mass of the second boat is 80 kg. After the boy on the second boat pushes away the first boat, the second boat acquires a velocity of 1.5 m/s. We need to find the velocity acquired by the first boat.

Solution

To solve this problem, we can use the principle of conservation of momentum. According to this principle, the total momentum before the interaction is equal to the total momentum after the interaction.

The momentum of an object is given by the product of its mass and velocity. Therefore, we can write the equation for the conservation of momentum as:

(mass of first boat * velocity of first boat) + (mass of second boat * velocity of second boat) = (mass of first boat * final velocity of first boat) + (mass of second boat * final velocity of second boat)

Since the first boat is initially stationary, its initial velocity is 0. Therefore, the equation simplifies to:

(mass of second boat * velocity of second boat) = (mass of first boat * final velocity of first boat) + (mass of second boat * final velocity of second boat)

Substituting the given values into the equation:

(80 kg * 1.5 m/s) = (120 kg * final velocity of first boat) + (80 kg * 1.5 m/s)

Simplifying the equation:

120 kg * final velocity of first boat = 80 kg * 1.5 m/s

final velocity of first boat = (80 kg * 1.5 m/s) / 120 kg

final velocity of first boat = 1 m/s

Answer

The first boat acquires a velocity of 1 m/s after the boy on the second boat pushes away the first boat.

Explanation

According to the principle of conservation of momentum, the total momentum before the interaction is equal to the total momentum after the interaction. In this case, the momentum of the second boat before the interaction is equal to the combined momentum of both boats after the interaction. Therefore, the first boat acquires a velocity of 1 m/s.