Question

Train car A is at rest when it is hit by train car B. The two cars, which have the same mass, are stuck together and move off after the collision. How does the final velocity of train cars A and B after the collision compare to the initial velocity of train car B before the collision? The final velocity is double train car B’s initial velocity. The final velocity is the same as train car B’s initial velocity. The final velocity is half of train car B’s initial velocity. The final velocity is zero since train car B will stop.

Answer 1

Answer

C .The final velocity is half of train car B’s initial velocity

Explanation

According to the law of conservation of momentum given by the product of mass and velocity, the velocity will be slightly that of the initial one due to increased mass (double mass). Here at least half of the kinetic energy is lost. Momentum is conserved but kinetic energy is converted to other energy forms after an inelastic collision. Kinetic energy is conserved in elastic collisions.

Answer 2

Answer: C The final velocity is half of train car B’s initial velocity.

Explanation: