Ox is at rest on a table. what can you say about the forces acting on the box? the upward and the downward are balanced.

The upward and the downward are balanced.

We can establish that there is no net force, it implies that Normal force and the Weight should be of the same magnitude. It means the upward and the downward force are balanced. 

Explanation:

A box is at rest on a table. The resting state is zero acceleration, which could imply constant velocity or zero velocity.

As the box is on a table, we will take the zero velocity condition.The box will have a mass (M) and weight (W). Due to the fact that there are two surfaces in this situation we have a normal force (N), in this simple case such as an object resting upon a table, the normal force on the object is equal but in opposite direction to the gravitational force applied on the object (or the weight of the object).

Also, if we consider the microscopic contact of the surfaces, we could have the presence of a static friction force, which keeps the box at-rest state.

As the box is at rest state, according to the newton laws, we can establish that there is no net force, it implies that Normal force and the Weight should be of the same magnitude. It means the upward and the downward force are balanced.

Finally, we can conclude that we can establish that there is no net force, it implies that Normal force and the Weight should be of the same magnitude. It means the upward and the downward force are balanced. 

b.a device that inputs heat into a cool object