Mother Nature’s Rules
There are rules outlined in the Highway Traffic Act and then there are Mother Nature’s rules.
Break any of the rules of the Highway Traffic Act and if you are caught, you will be punished financially by means of a fine. If you so prefer, you will no doubt be given the opportunity to experience first hand the joys of our legal system. In court you will be allowed to explain to a judge why you were such an idiot, after which you will be punished financially by means of a fine.
Mother Nature on the other hand is less forgiving than a judge and does not tolerate idiots. Break any of her laws and you will always get caught, plus her punishment is immediate and oft times much more severe.
Sir Isaac Newton, in the 17th century tried to fathom Mother Nature’s rules as they pertain to dynamics and came up with what are today classified as – Newton’s Laws of Motion. They are in fact Mother Nature’s Laws but Sir Isaac, being who he was, took all the credit for himself. Regardless of whose laws they are, the one which has the most impact – sometime too literally – is the one pertaining to momentum.
Momentum
Momentum is the measure of mass times velocity. It is not something that most people readily understand, but the conservation of momentum is something that Mother Nature takes very seriously. Working with this product can be very rewarding for those souls who understand it – it can be devastating in the hands of those who haven’t a clue. Here’s how it works -
Just think of momentum as a reserve of energy and instead of trying to fathom what momentum is, let’s take a look at an example -
If a vehicle weighing 1600 kg is travelling at 100 km/h, it will have a momentum of 1600 x 100 or 160,000 units of momentum. Similarly, if a vehicle weighing 2000 kg is travelling at 80 km/h, it will also have 160,000 units of momentum because 2000 times 80 is 160,000. Both vehicles have the same momentum despite their differences in weight and velocity.
Now we mentioned that momentum is mass times velocity – NOT mass times speed. Velocity and speed are not quite the same thing. Velocity is speed but in a given direction. For example, if a vehicle is driving in a circle at a steady speed of 20 km/h, it’s speed is constant but its velocity is ever changing because the vehicle’s direction is forever changing. Every half turn of the circle, the vehicle is actually going in the opposite direction.
Understanding that momentum is mass times velocity helps us understand that momentum also has a direction. For example – try changing the direction of a moving vehicle and you will immediately feel some reluctance. The more momentum the vehicle has, the more reluctance you will encounter. This is because of the law regarding the conservation of momentum. For the vehicle to change direction, the momentum in one direction has to be gradually converted to momentum in the new direction.
One way to help change the direction of momentum is if there was less of it. This is why we reduce velocity before we come to a corner. The mass of the vehicle does not change therefore the only way we can reduce its momentum is to reduce velocity. Once we have the velocity of the vehicle low enough, we can now convert the energy into friction – the friction between the tires and the road – to gradually change the vehicle’s direction. In effect we change the momentum in one direction to momentum in another direction.
Don’t get confused, you do this all the time while you are driving – it’s just that you take this process for granted. The only time you don’t understand it is when you put your vehicle into the side of the road and say something like, ‘I don’t know what happened – it just went off the road.’ What happened was, you had the audacity to try and change too much momentum in one direction to momentum in another direction in too short a time and Mother Nature took exception to your impertinence.
As a general rule – don’t mess with Mother Nature!