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 260000 kg and a velocity of 0.32 m/s in the horizontal direction, and the second having a mass of 52500 kg and a velocity of - 0.14 m/s in the horizontal direction. What is their final velocity?

0.243 m/s

Explanation:

From law of conservation of motion,

mu+m'u' = V (m+m') ... Equation 1

Where m = mass of the first car, m' = mass of the second car, initial velocity of the first car, u' = initial velocity of the second car, V = Final velocity of both cars.

make V the subject of the equation

V = (mu+m'u') / (m+m') ... Equation 2

Given: m = 260000 kg, u = 0.32 m/s, m' = 52500 kg, u' = - 0.14 m/s

Substitute into equation 2

V = (260000*0.32+52500 * (-0.14)) / (260000+52500)

V = (83200-7350) / 312500

V = 75850/312500

V = 0.243 m/s