# Car Crash Web Quest

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In this case, my team of investigators was placed at the scene of a car crash where a Cadillac Escalade SUV that had a mass of 3000 kg rear ended a 2000 kg Subaru wagon. We had to come up with a detailed report about that mass, velocity, and momentum of both vehicles both prior to and after the collision. Right when received the problem we dove right in to find the initial velocity of both cars directly following the collision.

We used the skid marks distance which was 2 meters for the SUV and 24 meters for the wagon, and acceleration given to us by the auto expert when the brakes are locked which were -2 m/s/s for the SUV and -3 m/s/s for the wagon. Using these numbers we plugged them into the equation VF^2=VI^2+2(a) (d). We figured out the velocity immediately following the collision of the SUV was 2.83 m/s while the wagon was 12 m/s.

After finding these figures, we plugged them into the equation P=MV to find momentum. Using the velocity that we found for each separate car we multiplied that by the mass of the individual cars and found that the momentum of the SUV before the accident was 8,485.28 N(S) and the wagon had a momentum of 24,000 N(S) directly after the collision.

And after learning the conservation of momentum law which is, the momentum before the collision has to be equal to the momentum after the collision, we realized we could solve for the velocity right before the crash by using the momentums and mass’ of the car. After setting up the momentum table we solved our equation which was 3000 kg(V) =32,490 N(S), to find the velocity before was 10.83 m/s. We came to this answer because the wagon had no momentum due to the fact it was stopped while the SUV had all the momentum.

Finally to find if the SUV was speeding, we set up the conversion table to find out how fast the SUV was going in km/hr. First we converted the m/s into m/hr to change the seconds into hours. Then we used the reference table to find how many km are in a meter which is 10^3. Following we multiplied the top parts and divided by 10^3 to find the SUV was speeding at a rate of 39 km/hr and was at fault for the crash and speeding.

Developed by: Andrew, R.J., and Liz

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