Question

ЗАДАЧАИз посёлков Озерки и Дубки,расстояние между которыми 100км,вышли одновременно И ПОШЛИ В одном направлении 2машины:грузовая и легковая.Скорость грузовой машины 70км/ч,а легковой,которая догоняет грузовую,-90км/ч.Через сколько часов легковая машина догонит грузовую?

Answer 1

Задача на движение
Дано:
v₁=90 км/ч
v₂=70 км/ч
S=100 км
tвстр.=? ч
Решение
1) vсближ. = v₁-v₂=90-70=20 (км/ч) - скорость сближения (движение вдогонку).
2) tвстр.=S:vсближ.=100:20=5 (часов) - легковая машина догонит грузовую.
ОТВЕТ: легковая машина догонит грузовую через 5 часов.

Answer 2

Problem Analysis

We have two cars, a truck and a passenger car, starting from two different villages, Ozerki and Dubki, which are 100 km apart. The truck has a speed of 70 km/h, while the passenger car has a speed of 90 km/h and is trying to catch up with the truck. We need to determine how many hours it will take for the passenger car to catch up with the truck.

Solution

To solve this problem, we can use the concept of relative speed. The relative speed is the difference between the speeds of the two objects involved. In this case, the relative speed between the passenger car and the truck is the difference between their speeds, which is 90 km/h - 70 km/h = 20 km/h.

The distance between the two villages is 100 km. Since the passenger car is trying to catch up with the truck, it needs to cover this distance while maintaining a relative speed of 20 km/h.

To find the time it takes for the passenger car to catch up with the truck, we can use the formula:

Time = Distance / Speed

In this case, the distance is 100 km and the relative speed is 20 km/h. Plugging these values into the formula, we get:

Time = 100 km / 20 km/h = 5 hours

Therefore, it will take the passenger car 5 hours to catch up with the truck.

Answer

The passenger car will catch up with the truck in 5 hours.

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