What is the book’s total kinetic energy at the instant just before it strikes the floor?

Manjui: What is the book’s total kinetic energy at the instant just before it strikes the floor?
Imagine a book that is falling from a shelf. At a particular moment during its fall, it has a kinetic energy of 13 J and a potential energy with respect to the floor of 75 J.

I know that E_k = 1/2mv^2 and E_p = mgh but I have no idea how to even approach the solution to this question.

Q: What is the book’s total kinetic energy at the instant just before it strikes the floor?

Answers and Views:

Answer by Garrett O
The book’s potential energy will change into kinetic energy, until its kinetic energy is a maximum which occurs when its potential energy is a minimum.

So the final kinetic energy will be 75+13 = 88J

Answer by Carey
As the book is falling (accelerating due to gravity), it’s potential energy (PE) is being converted to kinetic energy (KE). So at the instant before the book hits the floor, all it’s PE has been converted to KE. So the answer is KE = 13+75 = 88J.