Which of the following wavelengths of light from distant stars and other objects are observable from the ground? (More than one may be observable)
(a) Ultraviolet (400 to 1 nm wavelength)
(b) Gamma-ray wavelength (0.001 nm and shorter wavelength)
(c) Visible (Optical) (700 to 400 nm wavelength)
(d) X-ray wavelength (1 to 0.001 nm wavelength)
(e) Near-infrared (10 ffm to 0.7 ffm wavelength)
(f) Long-wavelength radio (100 km to 10 m wavelength)
(g) Far- and mid-infrared (about 100 to 10 ffm wavelength)
(h) Intermediate-wavelength radio (10 m to 1 cm wavelength)
(i) Microwave radio (1 cm to about 100 ffm wavelength)

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.