The intensity of the light is to control the frequency of the speaker output. When the light intensity is at the maximum measurable, the frequency of the speaker should be at 5000 Hz. When there is no light (dark), the frequency of the speaker is 1000 Hz. The range of tones at intermediate frequencies should be continuous and proportional to the intensity of light. More sophisticated versions of this system can be used in devices that can "see" images such as a vision guided missile. Required:
Sketch the schematic for this circuit below.

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.