In a closed system, glider a with a mass of 0.40 kg and a speed of 4.00 m/s collides with glider b at rest with a mass of 0.40 kg. the two interlock and move off. what speed are they moving?

0.50 m/s

1.0 m/s

2.0 m/s

4.0 m/s

This is an example of a perfect inelastic collision. After the collision the two gliders move as one object. Since the system is closed, total momentum is conserved. 
P1 = P2P1 = PA1 + PB1, PA1 - momentum of glider A before collision                PB1 - momentum of glider B before collisionP1 = (0.40)(4.00) + (0.40)(0.00) = 1.60 kg-m/sP2 = (0.40 + 0.40)(v), v is the final velocity of the two objects1.60 = 0.80v
Therefore, v = 2.00 m/s

I hope my answer has come to your help. Thank you for posting your question here in . We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

The answer is the first one