Friday, March 27, 2009


Part 2 :

In this part 2, let me explain scientifically what happened. This this for anyone interested in the mechanic of crash. Otherwise, just remember to "Buckle Up" that enough!!!

In crash science, the importance principle is what we learned in our physic class, which mainly law of physic from our good old friend, Mr. Newton. The Momentum Law.

What is the momentum law? It is basically says : Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

What does it means?... Let go back to the egg and trolley experiment mentioned in part 1. When the egg and the trolley move at some velocity, it will have a momentum (define as "mv"). The momentum will depend on the mass and the speed of the egg and the trolley. The higher the speed the higher the momentum. The higher the momentum the more difficult to stop.

The egg will have the same momentum as the trolley during the motion. When the trolley stop the momentum of the trolley will be zero but the momentum of the egg is still there and this will result in the egg to fly forward and drop down the floor.

1. Egg and trolley momentum = mv
2. Trolley movement = 0 but the egg momentum is still the same.
3. The egg will fly forward due to its momentum and finally hit the floor.

Case of not wearing seat belt :

Similar thing happened when you are involved in an accident. You and your car will have a momentum when your car is moving. But when your car make sudden stop during the impact, the momentum in your body will throw you out of your seat. Your body will bounce back and fort inside the car and hit the hard interior part of the car. This will cause severe injury to your body and internal organ like the egg yolk will spill all over the floor.

Case of wearing seat belt :

On the contrary, if you are wearing seatbelt, during the impact you will be locked to the car. So your body momentum will be same as the car. When the car momentum becoming zero, your body momentum also will become zero. Therefore, you will not be thrown out of your seat as before. This will reduce the risk of injuries...

This what happened...........

Well.... happy driving....... remember too buckle up.... this 2 second of effort can safe your life......


1 comment:

  1. there is many confusion among public regarding car structure. When people see a car got severe crush during collision, they say the car is no good, like 'tin milo' and etc.

    i believe you can provide some insight on this. please share with us.