Question

What additional information you would need to calculate the mechanical energy of a book that was lifted to a height of 3.0 meters. In your answer, what formulas you need to compute mechanical energy?

Answer 1

You need the mass and velocity. (`E=U+K=mgh+1/2mv^2`)

Explanation:

Mechanical energy is the sum of `color(red)"potential energy"` and `color(blue)"kinetic energy"`.

Potential energy `U` is the energy that an object stores as a result of its position.
In this question, the object(a book) has gravitational potential energy. It is expressed by the equation `color(red)(U=mgh)`. Here, `m` is the mass of the object(`kg`), `h` is the height(`m`) and `g` is the acceleration of gravity(`g=9.8 ms^(-2)`).

Kinetic energy `K` is the energy that an object has in motion.
It is expressed as `color(blue)(K=1/2mv^2)`. `v` represents velocity.

Total Mechanical energy `E` is expressed by `E=U+K`.
You would need the mass(`m`) and velocity(`v`) of the book to complete the calculation.