- #1
rose3
- 4
- 0
Homework Statement
A drunken driver crashes his car into a parked car that has its brakes set. The two cars move off together (perfectly inelastic collision), with the locked wheels of the parked car leaving skid marks 8.0 m in length.
If the mass of the moving car is 2290kg and the mass of the parked car is 1150 kg how fast was the first car traveling when it hit the parked car?
Assume that the driver of the moving car made no attempt to brake and that the coefficient of friction between the tires and the road is 0.28.
Homework Equations
F=μN=μmg
ma=μmg
vf^2=vi^2+2ad
m1v1=m2v2
The Attempt at a Solution
I found the speed of the two cars after the collision.
a=μg= (0.28)(-9.8)=-2.744 m/s^2
vi^2=vf^2-2ad = 0-2(-2.744)(8.0)
vi=6.626m/s
[/B]
I found the speed of the moving car using the momentum equation.
v1=(m2v2)/m1=((3440kg)(6.626))/2290kg=9.95m/s
Apparently this answer is wrong.