Question

Internal injuries in vehicular accidents may be due to what is called the "third collision" The first collision is the vehicle hitting the external object. The second collision is the person hitting something on the inside of the car, such as the dashboard or windshield. This may cause external lacerations. The third collision, possibly the most damaging to the body, is when organs, such as the heart or brain, hit the ribcage, skull, or other confines of the body, bruising the tissues on the leading edge and tearing the organ from its supporting structures on the trailing edge.

A) Why is there a third collision? In other words, why are the organs still moving after the second collision?

B) If the vehicle was traveling at 60 mph before the first collision, would the organs be traveling more than, equal to, or less than 60 mph just before the third collision?

Explain your answers in essay form:

Answer 1

A.)

The troird collision is due to the organ movement after the 2nd collision. This collosion is caused due to the law of inertia.

Before any collision car, body and organs are travelling with same speed.

After 1st collision car experiences a force and comes to rest suddenly.

But the driver is still moving with his body and internal organs intact. Hence after the 2nd collision the external body of the driver experiences a force through the windsheild or dashboard in order to make it stop as it has gained momentum which needs to be stopped due to external force.

Similarly we can say that the organs have yet to experience a force in order to stop as they are still moving inside the body with same speed as the body before 2nd collision.

Hence they experince the collision with the internal body or with the pipes or blood vessel to which they are connected to. This causes rupture or serious damage in order for the organs to come at rest from such such great speed.

b.)

Law of inertia - Every body will remain in the state of rest or of motion (in this case motion) until and unless any external force is provided to the system.

The organs would be travelling with same speed i.e. 60kmph as they have yet to experience an external force in order to have any change in speed for the law of inertia to be valid.