Velocity of system!?

Question

A mine car, whose mass is 510 kg, rolls at a speed of 0.5 m/s on a horizontal track, as the drawing shows. A 150 kg chunk of coal has a speed of 0.60 m/s when it leaves the chute. Determine the velocity of the car/coal system after the coal has come to rest in the car.

tried this solution, but it doesnt work, any ideas?

m1V1 + m2V2=(m1+m2)V3

V3= (m1V1 + m2V2)/(m1+m2)
V3=(510 x 0.5 + 150 x 0.60)/(510 + 150)
V3=0.52 m/s

its the velocity TO THE RIGHT --->

http://img256.imageshack.us/img256/4427/736altpr1.gif

Answer 1

The car is constrained to move horizontally only. You have to compute v2 as the horizontal component 0.6*cos(25 deg).