Question

A freight train car with a mass of 1.2 × 104 kilograms, travelling with a velocity of 23 meters/second, collides with a stationary freight train car of equal mass. What is the momentum of the system after the collision?
either:

A.
1.2 × 105 kilogram meters/second




B.
1.4 × 105 kilogram meters/second




C.
2.4 × 104 kilogram meters/second




D.
2.8 × 105 kilogram meters/second

Answer 1

D

Answer 2

\[(1200kg)(23 m/s)+(12000kg)(0 m/s) = p_3\]

p3 is essentially going to be them both together however the one object had no momentum so all the momentum from the first train has to equal what comes out so.

\[12000kg(23 m/s)=27600 kgm/s =27600 N*s=2.8*10^5 N*s\]