# Kinematics Problem: Train braking and blocking an intersection

• Zacharrry
In summary, the problem involves a train that is 400 meters long and is moving at a speed of 21.6m/s. The engineer applies the brakes at a crossing and the last car passes the crossing with a speed of 5.0m/s. To determine the time the train blocked the crossing, we can use one of the "big four" kinematics equations. One possible solution is 37.04 seconds, but to confirm the accuracy, we need to see the steps and formula used to solve the problem.
Zacharrry

## Homework Statement

A train 400 m long is moving on a straight track with a speed of 21.6m/s. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 5.0m/s. Assuming constant acceleration, determine how long the train blocked the crossing. Disregard the width of the crossing.

## Homework Equations

One of the "big four" kinematics equations (velocity, initial velocity, time, acceleration, etc.)

## The Attempt at a Solution

I tried the problem and got 37.04 seconds, but it told me it was incorrect. I am not sure what I did wrong, so can anyone help by telling me what they got and/or how to solve it?

You need to show what you did, which of the big four formulae you used, what numbers you put in, etc.

berkeman

## 1. What is kinematics?

Kinematics is the branch of physics that studies the motion of objects without considering the forces that cause the motion.

## 2. What is a kinematics problem?

A kinematics problem involves analyzing the motion of an object or system using equations and principles of kinematics, such as displacement, velocity, and acceleration.

## 3. How does train braking affect the motion of a train?

When a train brakes, it reduces its velocity and eventually comes to a stop. This change in velocity is caused by the force of friction between the train's wheels and the tracks.

## 4. Why is blocking an intersection a safety concern?

Blocking an intersection can cause traffic congestion and delays, as well as increase the risk of accidents. It also prevents emergency vehicles from passing through, potentially hindering their response time to emergencies.

## 5. How can kinematics be applied to train braking and blocking an intersection?

In the context of train braking and blocking an intersection, kinematics can be used to calculate the distance needed for a train to come to a complete stop and the time it takes for the train to do so. It can also be used to determine the impact of a blocked intersection on traffic flow and potential risks.

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