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Could the Futuristic Traveling Tube Become a Reality?It sounds like something straight out of a science fiction movie or a silly cartoon: a futuristic traveling tube that can quickly shoot people wherever they want to go, inside a tiny pod. But this may be just around the corner for people looking for a faster, easier, and cheaper-than-ever way to travel. South African-American inventor and billionaire Elon Musk, who, in the past, has worked on both private space flight and electric cars, recently announced he has been working on the design of this traveling tube, which could forever change th已知向量a，b满足|a|=1，|b|=3，a、b之间的夹角为60°，则a•(a+b)=5252．