Question

One object is at rest and another is moving. The two collide in a one-dimensional,
completely inelastic collision. In other words, they stick together and move off with
shared velocity. The speed of the object that is moving initially is 25 m/s. The masses of
the two objects are 3.0 and 8.0 kg. Determine the final speed of the two-object system
after the collision for the case when the large-mass object is the one moving initially and
the case when the small-mass object is the one moving initially.

Answer 1

Case #1:
Momentum = m1V1-m2V2 =8*25-3*0 = 200

Momentum = (m1+m2)V = 200
(8+3)*V = 200
V = 18.18 m/s

Case #2:
Momentum. = 3*25-8*0 = 75

(m1+m2)*V = 75
(8+3)*V = 75
V = 6.82 m/s