The atomic number of magnesium is 12. Its nucleus must contain A) 6 protons and 6 neutrons. B) 6 neutrons and 6 electrons. C) 12 neutrons and no protons. D) 12 protons and no electrons.

How have physicists played a role in history? A. Physics has changed the course of the world. B. History books are written by physicists. C. Physicists have controlled most governments. D. Most decisions about wars are made by physicists.

What is the original source of energy that drives the wind?

Three forces act on an object. Two of the forces are at an angle of 100◦to each other and have magnitude 25N and 12N. The third is perpendicular to the plane of these two forces and has magnitude 4N.

An automatic response to a stimulus is called a reflex.

There are two tuning forks struck at the same time. One tuning fork is tuned to a frequency note of 500 Hz. The other is tuned to a frequency of 487 Hz. How many beats will occur in 2 seconds?

Under what conditions will an object experience a gravitational force? Under what conditions will an object experience an electric force? Under what conditions will an object experience a magnetic force?

A basketball player pushes down with a force of 34 N on a basketball that is inflated to a gauge pressure of 9 x 104 Pa. What is the diameter of contact between the ball! and the floor?

Match these terms with their definitions: 1. unit of electrical resistance ampere 2. unit of electromotive force or electrical potential ohm 3. unit for measuring the strength of an electric current volt 4. unit of electrical power watt

In which is momentum conserved: an elastic collision or an inelastic collision?

List the types of radiation in order from least to most damaging.