How much kinetic energy is lost and how fat did they travel?

1) Momentum was conserved in the collision.
Momentum before = momentum after
m1*u1 + m2*u2 = (m1+m2)*v
where m1 = 1,500 kg, m2 = 1,300 kg, u2 = 0, and v = 8.1 m/s. Solve for u1. Use u1 to find the kinetic energy the van had before the collision. And calculate the KE the wreakage had immediately after. Subtract.

2) You have the energy the wreakage had immediately after the collision. The friction will do work equal to that energy in bringing them to a stop. Friction is given by
Ff = mu*N
where mu = 0.25 and N = the weight of the 2 vehicles = (m1+m2)*g

The work the friction does is given by
W = Ff*d
where d is the distance they slide and remember what I said about the work the fricition will do being equal to ...