Can you confirm a simple Physics Velocity Question?

[pinnacleprouk]

Homework Statement

Object a Mass 6kg moving velocity 5m/s is followed by a second object mass 8kg velocity 8m/s in the same straight line.

If the two objects are joined together after collision and move in the original direction, calculate heir common velocity.

The Attempt at a Solution

Now have either:

6x5 - 8x8 = 14V

-34 = 14V

-34/14 = V

V = -2.42m/s

or 5x6 + 8x8 = 14V

94 = 14V

94/14 = V

V = 6.71m/s

Which one is right?

Thanks in advance

 

[yaser1989]

The second one is right because both of the objects are moving in the same direction hence you would ADD the initial momentum of each mass.