# Help with Bunk Police Report/Two Part Collision

1. May 22, 2005

### jmontgom

Its been a while since Iv done basic Motion intro physics, or any for that matter :) I tried to solve for initial velocity of Saturn (below). However, The units and answer are not jiving. Please Help. I want to step through the equation.

Okay, Hwy Patrol made several mistakes per Accident Report. I have been working up a model for a two particle collision that evolved my 2003 Maxima 3,242 lbs (1,470.55 kg) and a 2001 Saturn SLI Curb Weight, 2, 332 lbs (1,057.78 kg) a month ago. The Sat Left a 10ft skid, KF Coefficient = .80 rubber on rd, on a pos 21 degree slope, After initial contact then deflecting at a 30 degree angle prior to skidding.

Known.

VoM = 25mph 11.17 m/s , VxM = 0mph, ωM = 1, 470.55 kg
VoS = ? , VxS = 0 mph , ωS = 1, 057.78 kg
θhill = 21°, θrS ≈ 30° (deflection Angle)
µS = .80 dS = 11.58 m (from contact to axS ≈ 0)
tSo = 0 tSf = ?

ax =Fxnet/m
ay =Fynet/m = 0
ω = m.gf
Fk= µk.N
Fs= µs.N
V² = Vo² + 2.a.d Equation 6
N= m.gf(Cosθ) (I think)

I ended up deriving axS as Equation 9
to figure out what the saturns speed
was if there were no initial contact.
I have also subtracted m2-m1 and still havnt found
what I am solving for... Vinital of Saturn.

Misfit

axS = 1/m(|-Fk| - wSinθ)
= 1/m(µk.m.gf.Cosθ - m.gf.Sinθ) Equation 9
Then inserting Equation 9 into Eq 6

VoS(initial) = √(-2*(µk.m.gf.Cosθ - m.gf.Sinθ)*d)
-----------------------------------
m

Also have tried

v1 = m1(Voy)/(m1-m2)Sinθ