When will Santa Claus arrive/Physics Christmas card

The physics Christmas card appears! ! The price is $15 a piece. The picture is a physics problem. Just calculate when Santa Claus will arrive! Size: 12*10.5 cm Envelope: +$1 (solid color cowhide envelope) There are five types of scientific Christmas cards: 1. When will Santa Claus arrive (Physics Christmas Card): If you calculate the physics puzzle in the picture, you can know how long it will take for Santa to arrive. 2. Why do red-nosed deer have red noses (Genetics Christmas card): Rudolph is the only deer with a red nose and is constantly teased by his friends. This Christmas card finally solves the mystery of the red nose?! 3. The evolution of Santa Claus The ancestors of Santa Claus were as early as 100 years ago, when humans lived with tools, Already holding the Christmas candy. "Merry Christmas." - Homo sapiens 4. Gas exchange in Christmas trees Christmas trees are still busy performing gas exchange at Christmas. 5. Dissecting a Christmas flower The red ones in Christmas flowers are the bracts, not the petals.