Finding particle one's final velocity in inelastic collision

[jheld]

Homework Statement

particle 1 with mass 6.7 kg going 7.3 m/s collides inelastically with a particle of mass 4 kg at rest. find the final velocity of particle one after the collision.

Homework Equations

Ki = Kf
but, mechanical energy is not conserved in an inelastic collision.
pi = pf (initial momentum = final momentum): mvi = mvf

The Attempt at a Solution

I decided to use the conservation of momentum because it is always conserved (at least for the problems I am dealing with).

m1vi1 + m2vi2 = (m1 + m2)vf
vi2 = 0
i have both particles at the same final velocity because they buckle together after the collision, therefore they share the same velocity.

vf = m1vi1/(m1 + m2) = (6.7*7.3)/(6.7 + 4) = 4.57 m/s

Is this correct?

 

[Doc Al]

Looks good!