Speed of collision problem?

Question

A 7500kg truck traveling at 5 m/s east collides with a 1500kg car moving at 20 m/s direction south of west. After the collision, the two vehicles remain tangled together. A) With what speed and direction does the entangled wreckage move immediately after the collision? B) If the coefficient of friction between the sliding wreckage and the road is .85, how far will the wreckage go before it slides to a stop?

I got:
A) (7500kg)*(5m/s) + (1500kg)*(20m/s) = )7500kg+1500kg)V
V= 7.5 m/s
is that right?

Answer 1

I will assume that South of West is a 45 degree angle towards the South.

momentum is conserved in North/South and East/West

East West
7500*5-1500*20*cos(45)=9000*vx
solve for vx
vx=1.81 m/s

North South
-1500*20*sin(45)=9000*vy
solve for vy

-2.36 m/s

The speed is
sqrt(1.81^2+2.36^2)
2.97 m/s

The direction is
atan(2.97/1.81) south of East
58.6 degrees south of East

B)
The KE of the wreck is
.5*m*2.97^2
and the work done by friction to stop the sliding is
m*g*µk*d

equating and solving for d
d=.5*2.97^2/(9.8*.85)
0.53 m
j