How does the energy of an electron change when the electron moves closer to the nucleus?
a. it doubles.
b. it increases.
c. it decreases.
d. it stays the same.

Aforce of 34.5 newtons is applied to an object at an angle of 45 º with the horizontal. what is the force acting on the object in the horizontal direction?

Awoman stands a distance d from a loud motor that emits sound uniformly in all directions. the sound intensity at her position is an uncomfortable 2.0×10-3 w/m2. at a distance 2.6 times as far from the motor, what are (a) the sound intensity and (b) the sound intensity level relative to the threshold of hearing?

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.