A 1.60-m tall person lifts a 2.10-kg book from the ground so it is 2.20 m above the ground. (a) What is the potential energy of the book relative to the ground? Number Units (b) What is the potential energy of the book relative to top of the person's head? Number Units 1 (c) How is the work done by the person related to the answers in parts (a) and (b)? same as (a) same as (b) average of (a) and (b) 2