# Tutor profile: Paulina V.

## Questions

### Subject: Physics (Newtonian Mechanics)

An object is subject to two forces that do not point in opposite directions. Is it possible to choose their magnitudes so that the object is in equilibrium?

Essentially, no. If there are only two forces acting on a system, and they are not in opposite directions, then the sum for all directions cannot be zero. Note that an object against a surface will be subject to the normal force, and that must be one of the two involved.

### Subject: Calculus

What kind of information we can obtain from the derivatives of a function?

The first and second derivatives determine the intervals of increase and decrease of a function, the maximum and minimum points, the interval(s) of concavity and points of inflections.

### Subject: Physics

¿When can you use the Gibbs-Duhem relation?

We can use the Gibbs-Duhem relation to verify thermodynamic consistency in our system description.