Question

Помогите пожалуйста решить физику. Даю не мало баллов. 2. Человек массой 60 кг, бегущий со скоростью 36 км/ч, догоняет тележку, движущуюся со скоростью 2 м/с и вскакивает на неё. С какой скоростью станет двигаться тележка, если её масса 15 кг? А) Рассчитайте импульс человека В) Запишите закон сохранения импульса после взаимодействия С) Рассчитайте импульс тележки и скорость, с которой будут двигаться вместе

Answer 1

Ответ:Дано:

m₁ = 60 кг

V₁ = 36 км/ч = 10 м/с

m₂ = 15 кг

V₂ = 2 м/с

___________

U - ?

Закон сохранения импульса:

m₁·V₁ + m₂·V₂ = (m₁ + m₂)·U

Скорость:

U = (m₁·V₁ + m₂·V₂) / (m₁ + m₂)

U = ( 60·10 + 15·2) / (60+15) = 8,4 м/с

Объяснение:

Answer 2

Problem Analysis

To solve this physics problem, we need to apply the principles of conservation of momentum and impulse. We are given the mass and initial velocity of the person, as well as the mass and initial velocity of the cart. We need to find the final velocity of the cart after the person jumps onto it.

Solution

Let's break down the problem into steps:

A) Calculate the impulse of the person. B) Write the law of conservation of momentum after the interaction. C) Calculate the impulse of the cart and the final velocity of the cart.

Step A: Calculate the impulse of the person

The impulse of an object is given by the product of its mass and change in velocity. In this case, the person's mass is 60 kg, and the initial velocity is 36 km/h. We need to convert the velocity to m/s before calculating the impulse.

1. Convert the person's initial velocity from km/h to m/s: - 36 km/h = 36,000 m/3600 s = 10 m/s

2. Calculate the impulse of the person: - Impulse = mass * change in velocity - Impulse = 60 kg * (0 m/s - 10 m/s) = -600 kg·m/s

Therefore, the impulse of the person is -600 kg·m/s. (Note: The negative sign indicates a change in direction.)

Step B: Write the law of conservation of momentum after the interaction

According to the law of conservation of momentum, the total momentum before the interaction is equal to the total momentum after the interaction. In this case, the momentum is the product of mass and velocity.

Let's denote the initial velocity of the cart as v1 and the final velocity of the cart as v2. The initial velocity of the person is 10 m/s.

The total momentum before the interaction is given by: - Initial momentum = (mass of person * initial velocity of person) + (mass of cart * initial velocity of cart)

The total momentum after the interaction is given by: - Final momentum = (mass of person * final velocity of person) + (mass of cart * final velocity of cart)

According to the law of conservation of momentum, the initial momentum is equal to the final momentum: - (mass of person * initial velocity of person) + (mass of cart * initial velocity of cart) = (mass of person * final velocity of person) + (mass of cart * final velocity of cart)

Step C: Calculate the impulse of the cart and the final velocity of the cart

We are given the mass of the cart as 15 kg. We need to find the final velocity of the cart after the person jumps onto it.

1. Rearrange the equation from Step B to solve for the final velocity of the cart: - (mass of person * initial velocity of person) + (mass of cart * initial velocity of cart) = (mass of person * final velocity of person) + (mass of cart * final velocity of cart) - (60 kg * 10 m/s) + (15 kg * 2 m/s) = (60 kg * final velocity of person) + (15 kg * final velocity of cart)

2. Substitute the values into the equation: - (600 kg·m/s) + (30 kg·m/s) = (60 kg * final velocity of person) + (15 kg * final velocity of cart)

3. Solve for the final velocity of the cart: - (600 kg·m/s) + (30 kg·m/s) - (60 kg * final velocity of person) = (15 kg * final velocity of cart) - (630 kg·m/s) - (60 kg * final velocity of person) = (15 kg * final velocity of cart) - 630 kg·m/s - 60 kg·m/s = 15 kg * final velocity of cart - 570 kg·m/s = 15 kg * final velocity of cart - final velocity of cart = 570 kg·m/s / 15 kg - final velocity of cart = 38 m/s

Therefore, the final velocity of the cart after the person jumps onto it is 38 m/s.

Summary

To summarize the solution: A) The impulse of the person is -600 kg·m/s. B) According to the law of conservation of momentum, the initial momentum is equal to the final momentum. C) The final velocity of the cart after the person jumps onto it is 38 m/s.

Please note that the calculations provided are based on the given information and assumptions made.