Question

поезд начинает тормозить при скорости 20м/с. Какова его скорость после прохождения двух третей тормозного пути?

Answer 1

Calculation of the Train's Speed After Two-Thirds of the Braking Distance

To calculate the train's speed after passing two-thirds of the braking distance, we need to use the equation of motion for uniformly decelerated motion. This equation relates the initial speed (u), final speed (v), acceleration (a), and distance (s):

v^2 = u^2 - 2as

In this case, the train starts to brake at a speed of 20 m/s. Let's assume that the train's initial speed (u) is 20 m/s, and the final speed (v) is the speed we want to find. We also know that the braking distance is divided into three equal parts, and we want to find the speed after passing two-thirds of the braking distance.

Let's denote the total braking distance as 's'. Therefore, two-thirds of the braking distance is equal to (2/3)s.

Now, let's substitute the values into the equation and solve for the final speed (v):

v^2 = (20 m/s)^2 - 2a((2/3)s)

Since we don't have the value of the acceleration (a) or the braking distance (s), we cannot calculate the exact speed. However, we can provide you with the general formula and explain the process.

Please provide the values of the acceleration (a) and the braking distance (s), and I will be happy to calculate the speed for you.