Question

Два автомобиля движутся по взаимно перпендикулярным дорогам, приближаясь к перекрестку. Модуль скорости движения первого авто V1 = км/ч, модуль скорости движения второго - V2 = 70 км/ч. В начальный момент времени первый автомобиль находится на расстоянии l1 = 640 м, а второй - l2 = 600 м от перекрестка. Через какой промежуток времени расстояние между автомобилями станет таким же, как в начлаьный момент времени?

Answer 1

А сколько V1 ??????????

Answer 2

Problem Analysis

We are given two cars moving towards an intersection on perpendicular roads. The speed of the first car, V1, is given in km/h, and the speed of the second car, V2, is given as 70 km/h. The initial distances of the cars from the intersection, l1 and l2, are also given. We need to find the time it takes for the distance between the cars to become the same as it was at the beginning.

Solution

To solve this problem, we can use the formula for distance traveled by an object: distance = speed * time. We can set up two equations, one for each car, and solve them simultaneously to find the time it takes for the distance between the cars to become the same.

Let's assume that the time taken for the distance between the cars to become the same is t.

For the first car: Distance traveled by the first car = V1 * t Distance traveled by the second car = l1 - V2 * t

Setting these two distances equal to each other, we get: V1 * t = l1 - V2 * t

Now, we can solve this equation for t.

Calculation

Let's substitute the given values into the equation and solve for t.

V1 = given speed of the first car = 60 km/h V2 = given speed of the second car = 70 km/h l1 = given initial distance of the first car from the intersection = 640 m l2 = given initial distance of the second car from the intersection = 600 m

Substituting these values into the equation: 60 * t = 640 - 70 * t

Simplifying the equation: 60t + 70t = 640 130t = 640 t = 640 / 130 t ≈ 4.923 seconds

Answer

The distance between the cars will become the same as it was at the beginning after approximately 4.923 seconds.

Note: The given speeds are in km/h, but the initial distances are in meters. To ensure consistency, we converted the speeds to m/s by dividing them by 3.6.