Which idea is found in BOTH " A Brief History of the Internet" and "Get Wiki Wise?

i dont understand but i think it is the two top ones

what question do you need answered?

two 125 kg bumper cars are moving toward each other in opposite directions. car x is moving at 10 m/s and car z at −12 m/s when they collide head-on. if the resulting velocity of car z after the collision is 10 m/s, what is the velocity of car x after the collision?