Complete question:
Imagine a book that is falling from a shelf. At a particular moment during its fall, the book has a kinetic energy of 25
J.
What was the initial potential energy of the book, and what is its total kinetic energy at the instant just before it strikes the floor?
Answer:
the initial potential energy = 25 J
the total kinetic energy is 50 J
Explanation:
At any instant of fall the potential energy will be converted to kinetic energy.
At the instant when the kinetic energy is 25 J, the initial potential energy has been converted to 25 J
Thus, the initial potential energy = 25 J
The instant just before it strikes the floor, the potential energy has been converted to kinetic energy.
Total kinetic energy = 25 J + 25 J = 50 J
