Train cars are coupled together by being bumped into one another. Suppose two loaded train cars are moving toward one another, the first having a mass of 150,000 kg and a velocity of 0.300 m/s, and the second having a mass of 95,000 kg and a velocity of - 0.120 m/s. (The minus indicates direction of motion.) What is their final velocity?

Answer: 0.137 m/s

Explanation:

from the question we are given the following

mass of train A (Ma) = 150,000 kg

velocity of train A (Va) = 0.3 m/s

mass of train B (Mb) = 95,000 kg

velocity of train B (Vb) = - 0.12 m/s

final velocity (V) = ?

mass of both trains = 245,000 kg

to solve this question we apply the conservation of momentum

MaVa + MbVb = (Ma + Mb) x V

V = (MaVa + MbVb) / (Ma + Mb)

V = ((150,000 x 0.3) + (95,000 x (-0.12))) / (245,000)

V = - 33600 / 245,000

V = 0.137 m/s