Potential Energy as stored work in a falling object...?

Question

You drop a 2.00 kg textbook to a friend who stands on the ground 10.0 m below the textbook with outstretched hands 1.50 m above the ground. (a) How much work W^grav is done on the textbook by the gravitational force as it drops to your friend’s hands? (b) What is the change ΔU in the gravitational potential energy of the text book – Earth system during the drop? Of the Gravitational potential energy U of that system is taken to be zero at ground level, what is U when the textbook (c) is released and (d) reaches the hands? Now take U to be 100 J at ground level and again find (e) W^grav (f) ΔU, (g) U at the release point, and (h) U at the hands. Explain your answers and clarify your work. Good Luck!!

Answer 1

1. Have your friend toss the book back up to you.
2. Read the book. (It's a physics book, right?)
3. With the information gained by reading the appropriate chapter of the book: DYOH!!

Answer 2

Quite a bit of work for 10 points....