Two cars of the same mass collide at an intersection. just before the collision, one car is traveling east at 80.0 km/h and the other car is traveling south at 60.0 km/h. if the collision is completely inelastic, so the two cars move as one object after the collision, what is the speed of the cars immediately after the collision?

Explanation:

In a completely inelastic collision the momentum P is conserved, so can be expressed as:

As P is defined as:

Replacing:

(Eq. 1)

As the problem says that the two cars have the same mass:

And in a completely inelastic collision the velocities after the collision are equal, so:

So replacing in Eq. 1:

Solving for :

And replacing the values for the velocity:

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )