Select the sentence that best describes why plastics and rubbers are good insulators.

a. in order for a material to be a good insulator, the electrons must be able to move freely into and out of the atom. atoms of plastics and rubber have electrons that are able to move freely.

b. many materials like plastics and rubber do not have any loosely bound electrons in their outer shell making it difficult, if not impossible, for electrons to move between atoms.

c.
plastics and rubber atoms have the same number of neutrons and electrons. this allows them to share electrons with other materials resulting in an electric current that can flow freely.

d. the free flowing arrangement of the plastic and rubber atoms make them able to freely accept electrons and allow the flow of electricity.

The correct option is (b).

Explanation:

Insulators: These are the materials which do not allow flow of electrons. They are not good conductor of electricity. The electrons of the insulator are not free to move. They are not loosely bounded in their outer shell. They have high resistivity. They offer high resistance to the flow of electrons.

Plastics and rubbers are good insulators. That's why the plastics and rubbers are used against the flow of electrons. They do not allow current to pass through them.

Conductors: These are the materials which allow flow of electrons. They are  good conductor of electricity. Here, the electrons are loosely bound in their outer shell.

Therefore, the correct answer is "Many materials like plastics and rubber do not have any loosely bound electrons in their outer shell making it difficult, if not impossible, for electrons to move between atoms".

be subject to a force andchange its motion

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.