A 10 kg cart is moving to the right at 5 m/s and hits a stationary 8 kg cart. The two carts stick together after the collision. What is the final velocity of the two carts?

Sorry i dont understand the question can you rephase it?

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

Ithink that the answer is b