B-1

[|Period 2 SSJI Group Contract.doc] (all i did was put exhibit numbers as well as cut out things that didn't make sense. Make sure you guys approve)

4/19/10 Group Members: Sarah Caspari Sean Barron Ian Gottheim Jinhoo Kim

We assigned the roles for each person, as shown in our contract. We also read over the crash data and began comprehending what occurred.

4/20/10

We learned and put crash reconstruction into application with a presentation from two people from the crash reconstruction team for bergen county.

4/21/10

We began discussing our approach for finding all of the information necessary for the project.

4/22/10

As a class we began to discuss momentum on two axes.

4/23/10

We used 2 disks to simulate a crash. With these disks, we did one crash that was elastic and one that was perfectly inelastic.

4/26/10

__Exhibit 1 Weights and wheelbases of cars__ Weight of 2002 Subaru Forster - 3152.6 lbs= 1430.00 kg Wheelbase= 99.4 in. Front damage

Weight of 2005 Ford Focus - 2654 lbs = 1203.83 kg Wheelbase = 103 in. Driver side damage

[|Subaru specs] [|Ford Focus specs]

__Exhibit 2__ __Exhibit 3__

Woodcliff Ave- 35 mph Mill Road- 25 mph  4/27/10 Crush Lab Data

4/28/10 __Exhibit 4 Skid Mark Measurements__ Measured skid marks __MV1:__ Left- 14.375 feet Right- 8.75 feet __MV2:__ Left- 11.875 feet Right- 8.75 feet Cars came to a stop 26.25 feet from the point of collision. Distance from pavement to grass - 16 feet Distance on grass - 10 feet

4/29/10 __Exhibit 5 Point of Collision Angles__ Point of collision angles MV1+MV2 = 155 degrees from point of collision MV1= 340 degrees from point of collision MV2= 110 degrees

Drag Coefficient = .708 (from graph with drag sled) Percent Braking= 100 % (both cars had sufficient brakes and skids show breaking by both cars)

4/30 Distance from pavement to grass - 16 feet Distance on grass - 10 feet

5/2/10 (see if you guys think this makes sense)

__Exhibit 6 Calculation for initial velocity of Subaru__ (Using 21.58 m/s for KE final of Subaru) (3.524 meters was found converting from the average of the two skid marks of mv1 in feet)

KE = W(breaking) + KE .5mv*v= F*D + .5mv2 .5(1430 kg)(v*v) = .708(9.8)(1430)*3.524meters + .5(1430)(21.58)(21.58) v = 22.68 m/s v = 50.73 mph (this is subaru's initial speed in mph)

__Exhibit 7 Calculation for initial velocity of Ford__ Initial speed of Ford (using 23.4 mph as final velocity) 23.4 mph = 10.46 m/s

average skid mark =10.31 ft = 3.14 meters

KE = W(breaking) + KE .5mv*v= F*D + .5mv2 .5(1203.83 kg)(v*v) = .708(9.8)(1203.83)*3.14meters + .5(1203.83)(10.46)(10.46) v = 12.37 m/s v = 27.7 mph (this is ford's initial speed in mph)

__Exhibit 8 Post Collision speed of cars when linked__ Post Collision speed of cars asphalt sqrt(30*d*f*n) sqrt(30*16*.708*1) 18.43 mph (speed on asphalt)

(.45 is found on edHeads, so this is used for the breaking on grass) grass sqrt(30*d*f*n) sqrt(30.10*.45*1) 11.62 mph

sqrt(18.42^2 = 11.62^2) 21.095 mph (combined post collision speed on asphalt and grass)

method 2 to find post collision speed using momentum m1v1cos340 = m2v2cos110 = m3v3cos155 (1430)(21.58)cos340 + 1203.83(10.46)cos110 = 2633.83(v3)cos155 23.12 mph rounded down to 23 mph

methods 1 and 2 are similar to verify results

__Exhibit 9 Initial Information of Crash Scene__

__Exhibit 10 Information to get speed of Subaru at Impact using Crush Energy__

__Exhibit 11 Drag Coefficient Graph__



__Summary of Findings__ MV1 Initial speed- 50.73 mph (15 mph over speed limit) Speed at contact- 48.23 mph Speed after contact - 21 mph or 23 mph (two different equations caused for close, but different answers0

MV2 (driver is dead) Initial speed- 27.7 mph ( 2 to 3 miles over speed limit) Final speed- 23.4 mph Speed after contact- (same as MV1)

 From EdHeads: force it takes to kill someone is 22,500 lbs--> 100,085 N. Crush energy was 734314.47 N*m; average d was 16.75 in-->.42545 m Force exerted is 1,725,971.254 N--> excessive speed caused death of driver of MV2 WITH ROUNDING IN DEFENSE'S FAVOR: -total crush energy is 700,000 N*m -using largest crush depth (21) to make the newtons smallest so they can't accuse us of overestimating, convert to meters-->.5334 -divide to get newtons (cancel meters)--> 1,312,335 N--> much more than it takes to kill a person.

[|Subaru Forester Picture] [|Ford Focus Picture]--- 5/3/10 -We are beginning to put the presentation together with our information, as well as creating questions that our lawyer can ask the witnesses.