import "newmath"
Перехват российских Ту-142 у Аляски дюжиной самолетов объяснили20:45，推荐阅读立即前往 WhatsApp 網頁版获取更多信息
I know, the idea of an inert table pushing up on a book doesn’t seem very normal. Maybe it’ll help if you realize that gravity doesn’t pull you to Earth’s surface, as people often think—it pulls you to the center of the Earth. The normal force is what keeps you from plunging through the floor. (By the way, “normal” means perpendicular—it’s always perpendicular to the surface.)，详情可参考手游
Фото: Staff Sgt. Gerald Willis / Globallookpress.com