A 2000kg car traveling at 10m/s collides with a 3000kg car that is initially at

Question

A 2000kg car traveling at 10m/s collides with a 3000kg car that is initially at rest at a stop light. The cars stick together and move 2m before friction causes them to stop. Calculate the coefficient of kinetic friction between the cars and the road, assuming that their negative acceleration is constant.

I used Pi=Pf to find the velocity of the two stuck together cars after the collision which was 4m/s. Do I use Wnc(work done by non-conservative force)=Ef-Ei?

-Fk=Ef-Ei? I am unsure how to set that up and work it out.

Explanation / Answer

onservation of mometum

2000 * 10 + 3000 * 0 = ( 2000 + 3000 ) V ;

V = 4 m /s

friction part ,

1/2 ( 2000 + 3000 ) V^2 = F .d

1/2 ( 2000 + 3000 ) V^2 = N.d

1/2 ( 2000 + 3000 ) V^2 = mg .d   

1/2 ( 2000 + 3000 ) V^2 = ( 2000 + 3000 )g .d

1/2 V^2 = g .d

0.5 * 4^2 = * 9.8 * 2 ;

= 0.408 <---------ans

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