Final answer:
The gravitational potential energy of the book relative to the floor is 7.83 J.
Step-by-step explanation:
The gravitational potential energy of an object is determined by its mass, the acceleration due to gravity, and its height relative to a reference point. In this case, the book has a mass of 0.45 kg and is 1.8 m above the floor. To calculate its gravitational potential energy, you can use the formula:
Gravitational Potential Energy = mass * acceleration due to gravity * height
Substituting the given values, the gravitational potential energy of the book relative to the floor is:
Gravitational Potential Energy = 0.45 kg * 9.8 m/s² * 1.8 m = 7.83 J