Question

If a train is travelling due north and its brakes are applied, will it have?

Answer 1

Hint: Let us just imagine the situation with all the directions kept in mind.Let us represent the situation using the X and Y axis. Let the direction of the positive X axis represent North ( $N$ ) , and negative X axis represent South ( $S$ ) . Let the negative and positive Y axis represent East ($E$ ) and West ($W$ ) respectively.

Complete answer:
Let’s draw a diagram and imagine the situation. Understanding direction(vector) is the main concept involved in the problem. The train travels north, thus we take north as a positive X axis.

Now if we observe we can see that the train is travelling north , and thus its acceleration is towards North $N$. Now if we apply a brake, this is seen as a deceleration for the train, hence its easy to say using the given directions, that a deceleration towards the North would serve as an acceleration towards the South $S$. Thus the concept of vector tells us that the brake applied while moving towards the North will cause an acceleration towards the South. Here we do not involve east and west directions as there are no mention of any angle or direction related to east and west.

Note:These questions often contain another part regarding the role of east and west directions. If we consider an angle and the brake is applied, we can get components along the other two directions also, so make sure you understand the concept of the coordinates and the directions. For answering these types of questions, always try to get the concept of what they are asking and answer accordingly. The main thing is the concept of directions.