Two magnets rest on a table. Because like poles of a magnet repel each other, the magnets exert a force on each other. If magnet 1 is moved closer to magnet 2, magnet 2 will move. This is because-

A. Objects need to touch each other in order to cause movement.

B. Magnets can only exert a force on other magnets.

C. Force can affect objects over distance.

D. Moving magnet 1 changed the force needed to move magnet 2

An electromagnet is a material in which the current produces electromagnetism and is passed to the core.  so to fill in the blanks, choices would be better if there were.an electromagnet is a magnet produced by electric current with a metal core

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)