Question

A 2,300-kilogram railroad car moving at 6 m/sec to the east collides with a 6,400-kilogram railroad car moving at 3.2 m/sec to the west. If the cars couple together, what is their velocity after the collision?

Answer 1

Answer:If the cars couple together then, the velocity after collision is 0.76 m/s in west direction.

Explanation: First car moving in east direction and second car moving in west direction. If the cars move couple together after collision. This collision called perfect inelastic collision.

Given that,

Mass of first car $m_{1} = 2300\ kg$

Initial velocity of first car $u_{1} = 6\ m/s$

Mass of second car $m_{2} = 6400\ kg$

Initial velocity of second car $u_{2} = -3.2\ m/s$

Because second car moving in opposite direction.

We know that,

$m_{1}u_{1} +m_{2}u_{2} = (m_{1}+m_{2})v$

$2300\ kg\times6\ m/s + 6400\ kg\times(-3.2)m/s = (2300+6400)\ v$

$v = \dfrac{(13800-20480)\ kg\ m/s}{8700\ kg}$

$v = -0.76\ m/s$

Hence, if the cars couple together then, the velocity after collision is 0.76 m/s in west direction.