Question

Допоможіть з завданням будь ласка ДАЮ 100 балів Обчислить гальмівний шлях і час гальмування автомобіля якщо він рухався прямою горизонтальною ділянкою дороги й перед початком гальмування мав швидкість 72км/год. Коефіцієнт тертя ковзання гуми по бетону - 0.75. Виконайте пояснювальний малюнок на якому вкажіть всі сили, що діють на автомобіль

Answer 1

Ответ:     26,7 м       2,7 с

Объяснение: Див. додаток

Answer 2

To calculate the braking distance and braking time of a car, we need to consider the initial velocity, coefficient of friction, and other forces acting on the car. Let's break down the problem step by step.

Given information:

- Initial velocity (v0) = 72 km/h - Coefficient of friction (μ) = 0.75

Calculating the braking distance:

The braking distance can be calculated using the formula:

Braking distance = (v0^2) / (2 * μ * g)

Where: - v0 is the initial velocity - μ is the coefficient of friction - g is the acceleration due to gravity (approximately 9.8 m/s^2)

Converting the initial velocity from km/h to m/s: - v0 = 72 km/h = (72 * 1000) / 3600 m/s ≈ 20 m/s

Substituting the values into the formula: - Braking distance = (20^2) / (2 * 0.75 * 9.8) ≈ 13.61 meters

Therefore, the braking distance of the car is approximately 13.61 meters.

Calculating the braking time:

The braking time can be calculated using the formula:

Braking time = v0 / (μ * g)

Substituting the values into the formula: - Braking time = 20 / (0.75 * 9.8) ≈ 0.36 seconds

Therefore, the braking time of the car is approximately 0.36 seconds.

Forces acting on the car:

When the car is braking, the following forces are acting on it: 1. Friction force (Ff): This force opposes the motion of the car and is responsible for the deceleration. It can be calculated using the formula:

Ff = μ * m * g

Where: - μ is the coefficient of friction - m is the mass of the car - g is the acceleration due to gravity

2. Weight force (Fw): This force acts vertically downward and is equal to the weight of the car. It can be calculated using the formula:

Fw = m * g

Where: - m is the mass of the car - g is the acceleration due to gravity

3. Normal force (Fn): This force acts perpendicular to the surface of the road and is equal to the weight of the car. It can be calculated using the formula:

Fn = m * g

Where: - m is the mass of the car - g is the acceleration due to gravity

4. Net force (Fnet): This force is the vector sum of all the forces acting on the car. It can be calculated using the formula:

Fnet = Ff - Fw

Where: - Ff is the friction force - Fw is the weight force

Please note that the mass of the car (m) is not provided in the given information. If you have the mass of the car, you can substitute it into the formulas to calculate the forces.

I hope this helps! Let me know if you have any further questions.