Suppose the traffic investigators determined from the skid marks that these cars came to rest with a displacement of 9.72m at 72 degrees North of East, and the coefficient of friction was .72. The red car had a mass of 1000kg, but the blue car's mass was 1300 kg in this accident. Find the velocities (in mph) of each car immediately before their collision.(adsbygoogle = window.adsbygoogle || []).push({});

Solution: I used two formulas that I read in another forum but we have never been taught the first one in class. First I used ( Vf2-Vo2=-2UkgD) then M1V1i+M2V2i=(M1+M2)Vf

D=9.72

Theta=72 degrees

Uk=.72

M1=1000kg

M2=1300kg

1000kg*Vi+1300kg*0=(2300kg)(11.71m/s)

=26.93m/s=60.3mph

1000kg*0+1300kg*Vi=(2300kg)(11.71m/s)

=20.72m/s=46.4mph

I got 60.3 mph for the Red Car and 46.4 mph for the Blue Car. Any idea if that is the correct way to go about this problem.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Inelastic Collision with Friction and angle

Can you offer guidance or do you also need help?

**Physics Forums | Science Articles, Homework Help, Discussion**