The "last from last" test paper of an elementary school student went viral. The teacher was so angry that he went to the parents, but the parents laughed out loud after reading it.
What are four-dimensional velocity and four-dimensional momentum? "Zhang Chaoyang's Physics Class" explains four-dimensional vectors and their transformations
During the decoration, 5 corners were cut in 5 places. If you are not careful, you will fall into a trap. The decoration novice can't afford to be hurt.