Question

каскадер начинает бежать со скоростью 5 м/с за движущимся грузовым автомобилем. Догнав его каскадер прыгает в его кузов и проезжает в автомобиле вдвое больше время, чем он его догонял, и спрыгивает с него. Найдите среднюю скорость каскадера за все время движения, если скорость автомобиля 4м/с

Answer 1

Условно можно разделить путь каскадера на 3 части:

1-бег за транспортом;

2-движение в транспорте;
3-движение в транспорте.

(т.к. в транспорте он проехал вдвое больше времени, чем догонял его)

 

Тогда средняя скорость движения:

(5+4+4)/3=13/3≈4,33 м/с.

 

Ответ: ≈4,33 м/с.

Answer 2

Problem Analysis

In this problem, a stuntman is running at a speed of 5 m/s to catch up with a moving truck. After catching up with the truck, the stuntman jumps into the truck and travels for twice the time it took to catch up with the truck. The average speed of the stuntman for the entire duration of the motion needs to be calculated. The speed of the truck is given as 4 m/s.

Solution

To find the average speed of the stuntman, we need to calculate the total distance traveled by the stuntman and divide it by the total time taken.

Let's assume the time taken to catch up with the truck is t seconds. Since the speed of the stuntman is 5 m/s and the speed of the truck is 4 m/s, the distance covered by the stuntman to catch up with the truck is 5t meters.

After catching up with the truck, the stuntman jumps into the truck and travels for twice the time it took to catch up with the truck. Therefore, the total time taken by the stuntman is 3t seconds.

The distance traveled by the stuntman inside the truck can be calculated by multiplying the speed of the truck (4 m/s) by the time spent inside the truck (2t seconds). Therefore, the distance traveled inside the truck is 8t meters.

The total distance traveled by the stuntman is the sum of the distance traveled to catch up with the truck and the distance traveled inside the truck. Therefore, the total distance traveled is 5t + 8t = 13t meters.

The total time taken by the stuntman is 3t seconds.

To find the average speed, we divide the total distance traveled by the total time taken: Average speed = Total distance / Total time = (13t meters) / (3t seconds) = 13/3 m/s.

Therefore, the average speed of the stuntman for the entire duration of the motion is 13/3 m/s.

Answer

The average speed of the stuntman for the entire duration of the motion is 13/3 m/s.