# Relative velocity… The mathematical problem we solve every day, unconsciously

When you studied relative velocity in your school mathematics class, did you imagine that it would be useful in real-life? Remember the boat, trying to cross a river flowing at a steady speed? Or the swimmer, crossing a river stream and trying to judge where he will land on the other side..

Cut to present..
Do you realize that you use relative velocity calculations in your daily life? And as you are reading this, it is safe to assume that you have solved the problems successfully, time and again.

To put it in a simple way, collisions happen because two objects cannot occupy the same space at the same time. And when you cross a busy road, you avoid collision with a vehicle by applying relative velocity calculations.

Has this thought ever struck you how complicated a relative velocity problem is this?

Theoretically speaking, this situation does not arise when you cross the road at traffic signals. Means, you cross the road only when vehicles come to standstill. Now the challenge is elsewhere, when you cross the road negotiating moving vehicles. Does it sound familiar? Actually, that is the way we cross our busy roads in India 😊.

When we do that, we assume a hell a lot of things: width of the road, speed of the oncoming car, the distance between us and that car, width of the car, speed of walking etc. Yes, there are so many things involved in the equation!

Among all these, only one thing is in our control: the speed of walking. And which is absolutely not under our control: the speed of the oncoming car, which is variable.

Needless to mention, we do not consider any other vehicle which is not in our sight. And we do not have any clue about the intentions the driver may have in his / her mind at that instant.

It really does not require a mathematical genius to say that it is a complicated problem. With so many variables and assumptions, it is impossible to determine whether collision with a vehicle can be avoided.

But, in real life, we are solving this problem every day, even without taxing our brain at all! Are we taking too much of risk? Or are we confident about our assumptions? Or is it just our gut feeling saving us?

Remember the old saying, “look right, look left before crossing the road”? Having done that, should we look right once again, just to be on a safer side?

Up to this, it is all about the pedestrian and the calculations s/he is making while crossing the road. Actually, there is another side of this situation, which makes the problem even more complicated. The car driver too has to do the same relative velocity calculations. S/he also is assuming all the variables involved. And the only thing can be controlled is the driving speed.

To make the matter even worse, there are more than one car involved in real life, all moving in different lanes, from different distances and at different speeds 😯.

Now, you know how complex the situation is. And what is the probability of everything going in your favour. Just think once, if any one of the assumptions made by the pedestrian or drivers goes wrong!

After reading this far, will you ever try crossing a busy road without a traffic signal?

Location: 12.97° N, 77.59° E | Interests: travel, movies, learning | Why Medium?: to share my observations, experiences and learn from others

## More from Debnath Goswami

Location: 12.97° N, 77.59° E | Interests: travel, movies, learning | Why Medium?: to share my observations, experiences and learn from others