For the following question, imagine the book drops in free fall and falls a distance d.
1. For the system of the book and earth, the change in total energy of the system if the book falls a distance d.
O positive.
O is negative.
O is zero.
O has a sign which cannot be determined.
2. For the system of the book and earth, the network done on the system by external forces as the book falls a distance d.
O is positive.
O is negative
O is zero.
O has a sign which cannot be determined.