Question Collision Energy Changes Practice Test

Keisha rolls a marble into three still marbles, and after the collision two marbles roll away. What would be a good scientific question to ask about this collision?

Yuki sets up a line of standing dominoes on a desk. She gently tips the first domino so it falls into the next one. Before each collision, one domino is moving and the next is still. After each hit, the next domino begins to fall. What question about motion and energy could this collision help answer?