Question

Youre a student in the General Physics 1 course. Your friend the lawyer, contacts you to consult the case of a client of his who has been injured in a traffic accident. The car of the client was rear-ended by another vehicle while stopped. The judge who is taking the case, argues that, if the vehicle of the affected had been in movement, the injuries would not have been as severe. Is the judge correct? Or do you think can I win this case? Investigate and make an argument based on the concepts studied in physics class (especially energy and momentum) and support your arguments with a development of mathematical equations that demonstrate their answer

Answer 1

To win the case we must consider the conservation of momentum and energy during the rear end collision.we must prove that the accident is really damaging with the help of physics.consider the case that the two vehicles are moving with different velocities and different mass,according to the conservation of momemtum initial momentum=final momentum which we can represent mathematically as given below, Pi=Pf where Pi=(m1*v1)+(m2*v2) where m1 is the mass of one vehicle and m2 is the mass of another vehicle,v1 is the velocity of one vehicle and v2 is the velocity of another vehicle.Then Pf=(m1+m2)v3 where m1 is the mass of one vehicle and m2 is the mass of another and v3 is the final velocity of both the vehicles.After collision the two vehicles travel as one for a small distance.From this we get the equation for rear end collision becomes, (m1*v1)+(m2*v2)=(m1+m2)v3

From this equation we can say that the collision really affect the vehicle whether it is moving or not and when the collision happens there is a transfer of energy and we know that when momentum is conserved energy is also conserved there.So when rear end collision occur if the affected person inside the car is wearing a seat belt there will be no external injuries seen according to the judge but there will be internal injuries related to spine and head of the person.These steps happen one by one suddenly after the rear end collision to the person in the car.

• As the car moves forward the spine straightens
• Lower neck is pulled forward causing the head to rotate backward
• Head and torso are accelerated forward ahead of the car seat

From these details it is clear that the accident is not simple and with the help of physics we got a clear picture of it.