When seen from an airplane, a rainbow sometimes forms a complete circle. When this happens, the plane's shadow is a. in the center of the rainbow. b. totally outside the rainbow. c. in the upper part of the rainbow. d. Nowhere. There is no shadow. e. in the lower part of the rainbow.

A. in the center of the rainbow

Explanation:

A rainbow is always seen half circle

For one to see the full circle of the rain bow, it will appear that the shadow of the object will be found in the centre of the rain bow.

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

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.