Question

Поезд движется со скоростью 20м/с. При включении тормозов он стал двигаться с постоянным ускорением 0,1 м/с2. Определите скорость поезда через 30 с после начала торможения.

Answer 1

Problem Analysis

We are given that a train is initially moving with a velocity of 20 m/s and then starts decelerating with a constant acceleration of 0.1 m/s^2. We need to determine the velocity of the train after 30 seconds of braking.

Solution

To solve this problem, we can use the equations of motion. The equation that relates final velocity (v), initial velocity (u), acceleration (a), and time (t) is:

v = u + at

Here, the initial velocity (u) is 20 m/s, the acceleration (a) is -0.1 m/s^2 (negative because it is decelerating), and the time (t) is 30 seconds.

Substituting these values into the equation, we can calculate the final velocity (v):

v = 20 + (-0.1) * 30

Calculating the expression:

v = 20 - 3

Simplifying:

v = 17 m/s

Therefore, the velocity of the train after 30 seconds of braking is 17 m/s.

Answer

The velocity of the train after 30 seconds of braking is 17 m/s.