At the highest point of a ball's flight when kicked upward, it has stopped moving upward entirely and has not started moving downward yet. It therefore has no speed or velocity. However, it is still accelerating at a constant rate for the entire flight, because the earth keeps on pulling on it with the same force throughout. Hope this helps!
When someone lifts a book from the ground, the work you use is positive. By lifting the book, you change it's energy and it's original place The book gains, kinectic energy.
