Which of the following forces require physical contact? A) tension
B) friction
C) applied force
D) air resistance
E) magnetic force

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.

Which two particles are found in the center of an atom

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon