When a glass rod is rubbed with silk, it becomes positive and the silk becomes negative—yet both attract dust. Does the dust have a third type of charge that is attracted to both positive and negative? Explain. g

The dust does have any third charge.

Explanation:

                In the context, the glass rod gets positively charged and so it induces a negative charge on the dust particles which are neutral. Thus the face of the dust particle which is near to the rod becomes negative charge and the opposite face of the dust gets equal positive charge and hence it ensures the neutrality of the dust particle but still being attracted to the glass rod.

               And in the case of the negatively charged silk, the silk induces or gives positive charge to the dust particle which is neutral in charge. The face which is near to the silk gets positive charge and the other face becomes negative charge, again ensuring its neutrality and being attracted to the glass rod.

               This shows how both positive charged rod and negatively charged silk attracts the neutral dust particle.

the answer is a. hope this .

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.