If you tie a thread to the middle of a water filled plastic bottle and pull slowly, the bottle moves. if you pull very rapidly, the thread breaks before the bottle can move. why?

Gettysburg address question. what is the purpose of this address?

What would be the most relevant question to ask to find out why tutankhamen died? what was tutankhamen’s age when he died? was a doctor with tutankhamen at his death? why was tutankhamen mummified after his death? did tutankhamen’s body have evidence of disease?

"there will be differences in degree of mood elevation seen in depressed clients after receiving either cognitive-behavioral or psychoanalytic therapy."; in this hypothesis, mood elevation is the: