A girl watches from inside a window as a stone goes sailing vertically up and then a little later falls down again past her view. She doesn't see it during the time it is above the top of her window (or below the bottom of the window either). Suppose the window is 6m from the bottom to top and she sees the stone for a total of 1s.

a) What is the time she sees the stone on the upward part of its motion?

b) What is the speed with which the stone was moving upward just when it passed the bottom of the window?

c) How high above the top of the window does the stone rise?