Mass of the book is $\"\"$ kg.

Height of the person is $\"\"$ m.

Person lifting the book from the ground.

Height of the book above the ground is $\"\"$ m.

Potential energy of the object is $\"\"$ .

Where $\"\"$ mass of the object and $\"\"$ height of the object.

Find the potential energy of the book relative to the ground.

Height of the book above the ground is $\"\"$ m.

Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

$\"\"$

Find the potential energy of the book relative to the top of the persons head.

Whenever calculting potential energy relative to the top of the person $\"\"$ s head consider the height of the

object above the person $\"\"$ s head.

Height of the object above the person $\"\"$ s head is $\"\"$ m.

Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

$\"\"$

The work done by the person in lifting the book from the ground to the final height is the same as the answer to part (A).

In part (A), the potential energy is calculated relative to the starting location of the application of the force on the book.

The work done by the person is not related to the answer to part (B).