an 7578 kg train car move to the right at 12m/sec. it collides with a 1744 kg Parked train car. The cars get stuck together and Roll Along the track. how fast in m / sec do they move after the collision?​

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. it strikes a red glider that has mass 0.600 kg and that is initially at rest. after the collision, the blue glider is moving to the left with a speed of 3.00 m/s.(a) what are the magnitude and direction of the velocity of the red glider after the collision? (b) is this collision elastic?